Modular package sorting system

ABSTRACT

The present invention relates to systems and methods for sorting a wide variety of packages, including, but not limited to, parcels, mail pieces, bundles, and other similar items. Embodiments of the invention specifically relate to interchangeable sorting modules with sort stations that may be used to quickly and accurately sort packages of varying shapes and sizes. Additional embodiments of the invention relate to a control architecture for operating the aforementioned interchangeable sorting modules. Such control architecture may comprise a programmable logic controller (PLC) for controlling each of the interchangeable sorting modules.

This application claims priority to U.S. application Ser. No.16/537,503, filed Aug. 9, 2019.

FIELD OF THE INVENTION

The present invention relates to systems and methods for sorting a widerange of parcels, mail pieces, bundles and other items commonly handledin e-commerce shipping facilities and distribution centers by utilizingmodular product transport components. More specifically, the inventionrelates to a control architecture for such modular sorters.

BACKGROUND

The volume of products being sorted and transported by material handlingsystems is rapidly increasing in the United States and worldwide. Muchof the volume increase can be attributed to the growth of e-commerce,whereby products are purchased over the Internet by consumers andbusinesses and delivered from fulfillment centers where individualorders are picked from shelved stock, packed and shipped directly to thepurchaser, without the intermediation of physical retail stores. Themajority of e-commerce shipments are below the scale of cases or palletsin size and weight.

Automatic sortation systems are a key technology enabling fulfillmentcenters and shipping organizations to prepare high volumes of orders forshipment and move them through a sometimes-complex physical distributionsystem to the purchaser. High speed, low cost, and automated operationsare key attributes for efficiency and competitiveness. Two of the mostcommon sorter types are the loop sorter and the linear sorter.

A loop sorter is typically housed in a large building and resembles asmall train with multiple package-holding segments (hereinafter “cars”or “sorter trays”) moving around a closed loop at speed. At one part ofthe loop, packages are moved onto individual cars at what are called“induction stations.” The packages at any given induction station mayhave a variety of shapes and/or sizes. As the sorter cars move aroundthe loop, there are a multitude of locations called “sort points” wherethe contents of the train can be moved off, or “sorted,” into containersor attached conveyors. Various methods are used to move the product offthe sorter car. Methods include tipping the car to the side, driving atransverse conveyor belt on top of the car, and dropping the productthrough the car via “bomb bay” doors.

Linear sorters perform the same transport and sorting function as loopstyle sorters. Linear sorters induct articles onto a singlestraight-line conveyor where all packages enter at the head of thesorter and are then expelled to containers positioned on the right orleft of the sorter spine. The conveyor has features that move packagesto the right or left at a precise time to discharge them into a waitingcontainer or further conveyor designated by the sorter system. Typicaldischarge methods include “shoes” whereby features embedded in theconveyor move right or left to push the package off the conveyor, and“pushers” whereby a stationary actuator external to the conveyor pushesthe package at the right moment off of the conveyor to the right orleft.

In more recent years, a different type of sorter has been developed thatutilizes a conveyor belt composed of many plastic or metal links withmultiple rotating or otherwise moveable elements embedded in theconveyor belt structure. The tops of the moveable elements contact theproduct being transported and the bottoms of the elements contact fixedor moving features underneath the conveyor belt. When these elementstouch features underneath the conveyor belt, their movement can becontrolled, thus changing the movement of the article on the top surfaceto divert it off the conveyor. The conveyor belt can be long, e.g. asingle belt for the entire sorter, or the belt can be broken intoshorter sections whose actions must be coordinated to obtain the desirednumber of discharge points for the sorter.

New designs, e.g. U.S. patent application Ser. No. 15/916,248, filedMar. 3, 2018, indicate how short sections of such linked belts can beused to build individual sortation modules, and multiple independentmodules, each capable of moving a package off the conveyor, can beconnected together to form sorters of different lengths. A sortercomposed of modular units may be configured to accommodate varyinginitial sort point and package size requirements, and modules can bereadily added or removed to accommodate changing needs.

SUMMARY

It is to be understood that both the following summary and the detaileddescription are exemplary and explanatory and are intended to providefurther explanation of the invention as claimed. Neither the summary northe descriptions that follow is intended to define or limit the scope ofthe invention to the particular features mentioned in the summary or inthe description. Rather, the scope of the invention is defined by theappended claims. In certain embodiments, the disclosed embodiments mayinclude one or more of the features described herein.

A new modular package sorter system combines a standard inductionsub-system with standardized sortation modules that are economical tomanufacture in quantity, thereby resulting in the configuration ofdifferent sized sorters. A distributed controls architecture and controlsoftware is the same for any size of sorter. Supervisory controlsoftware runs on a computer in the induction sub-system while aprogrammable logic controller (PLC) is incorporated with each sortmodule and controls the operation of each sortation module locally. Theindividual PLCs are programmed with identical control and communicationsfeatures. Each sortation module runs independently, yet coordinates thetransition of packages between one another. Each sortation module haslocal adaptive control features that can dynamically change speeds,detect jams, or respond to operator inputs independently withoutaffecting adjacent modules or burdening the supervisory control system.Collectively this provides a robust sorting solution that is scalable,cost-effective, reliable, and fault tolerant.

A new low-cost package sorter system design has a modular constructionand a distributed control architecture. It is to be understood that awide variety of items may be sorted by systems according to variousembodiments of the present invention, and that the term “package” is notmeant to be limiting. Everywhere the term “package” is used, the term“object” can be substituted. The term “packages” refers to mailpackages, which may be a wide variety of different shapes and sizes.Mail packages typically have information, particularly destinationinformation, encoded in some machine-readable form, typically a barcode. However, embodiments of the invention are useful for objectswithout machine-readable destination information, for example wheredestinations are ascertainable according to programmed logic dependingon characteristics of the object that can be determined by a computer orentered manually. For example, a meat processing plant might use such asystem, where destination is determined based on the size, shape, and/oranimal origin of a cut of meat, which information may be enteredmanually and/or detected automatically. The sorter system in embodimentshas two main sub-systems: the induction sub-system and the sortationsub-system.

The induction sub-system is where packages are introduced to the sorter.This sub-system is standardized for all sorters regardless of length ornumber of sort points. All induction systems use the same electroniccomponents, interconnect cabling, wiring, and support documentation.Standardized mechanical configurations make this sub-system low-cost tomanufacture. The control software also does not change with requirementsfor different sized sorters with different numbers of sort points.

The sorter control computer and system software is located in theinduction sub-system and provides overall control of the sorter systemto start up, shut down, manage the sort schemes, control the I/O bus,and interface with the data collection systems for the induction ofpackages. Sort schemes are rules that relate package sortation points topackage data and may be for example a table of correspondence thatrelates package data, particularly destination address, to sort pointdestination, so that packages are sorted to trucks (via their sort pointdestinations) that service routes in the area of their destinationaddresses. These sort schemes can change even within a day, for examplemail trucks may be divided into morning and afternoon routes and thesort schemes may change accordingly.

A display screen and keyboard at the sorter control computer provide thehuman machine interface (HMI) to operate the sorter, update sortschemes, and manage sorter operations. For example, an operator can turnthe system on or off (e.g. between standby mode and operating mode),read log files and other records, for example to see how many packageswere sorted to different points, average package weight, how many jamsor other errors were reported and where in the system, fault codes, etc.Typically when an error or other alert condition occurs, this will bereflected on the display and an operator can address the issue from theHMI, although operators may also be able to determine and address theproblem using local controls such as buttons/switches and indicatorlamps at other locations in the system.

The conveyor components in the induction sub-system are controlled bythe sorter control computer to move the package through a series ofstations to read package address information, determine dimensions, andweigh the packages. The sorter control computer collects the packageinformation and determines to which sort point destination on the sorterthe package should be transported.

Once the package sort point destination is determined, the sortercontrol computer prepares a data set specific to the package and sendsthis data to the first of a string of Programmable Logic Controllers(PLCs) that are installed in the series of sort modules that comprisethe sortation sub-system. The PLCs control the operation of the sortmodules, alone or in conjunction with the sorter control computer. Thesorter control computer uses this data set to hand off the transportcontrol to the series of PLCs formed by the string of sort modules.Although in a preferred embodiment, each sort module comes with its ownlocal PLC, in some embodiments a PLC may control a small group of sortmodules, or a single sort module may have more than one PLC to controlexpanded functionality of the module.

Although PLCs are well known and used throughout as the preferredexample, other controllers known in the art may also be used for thesame purpose. It should be appreciated that a variety of computingdevices may operate as controllers, and that controllers, as well as thecontrol computer, may include hardware, firmware and/or software.Generally, the configuration of a controller, control computer or othercomputing device may refer to particular logic embodied in hardware,firmware, and/or software. In other words, a controller or computerdevice may be configured to provide a certain functionality by providingappropriate logic programmatically with software, or embodied inhardware/firmware. Configurations of controllers described herein maytherefore refer to logical modules of the controllers that may becombined with other modules or divided into sub-modules despite theirphysical organization or storage. Where particular functionality isattributed to a controller or control computer, it may be effectuated byhardware, firmware, software or a combination thereof. Such software maybe a collection of software units, possibly having entry and exitpoints, written in a programming language, such as, but not limited to,SWIFT, Objective C, Java, Lua, C, C++, or C#. A software unit may becompiled and linked into an executable program, installed in a dynamiclink library, or may be written in an interpreted programming languagesuch as, but not limited to, BASIC, Perl, or Python. It will beappreciated that software units may be callable from other units or fromthemselves, and/or may be invoked in response to detected events orinterrupts. Software units configured for execution on computing devicesby their hardware processor(s) may be provided on a computer readablemedium, such as a compact disc, digital video disc, flash drive,magnetic disc, or any other tangible medium, or as a digital download(and may be originally stored in a compressed or installable format thatrequires installation, decompression or decryption prior to execution).Such software code may be stored, partially or fully, on a memory deviceof the executing computing device, for execution by the computingdevice. Software instructions may be embedded in firmware, such as anEPROM. It will be further appreciated that hardware modules may becomprised of connected logic units, such as gates and flip-flops, and/ormay be comprised of programmable units, such as programmable gate arraysor processors.

Controllers as referenced herein may in various embodiments be entirelylocal, entirely remote, or a combination thereof, and may use one ormultiple processors and hardware located in one or more locations,locally and/or remotely. The logic used to govern the configuration andoperation of the controllers and control computer(s) can be contained ona variety of signal-bearing media. Illustrative signal-bearing mediainclude, but are not limited to: (i) information permanently stored onnon-writable storage media (e.g., read-only memory devices within acomputer such as CD-ROM disks readable by a CD-ROM drive); (ii)alterable information stored on writable storage media (e.g., hard-diskdrive or solid state storage devices); and (iii) information conveyed toa computer by a communications medium, such as through a computer ortelephone network, including wireless communications.

The latter embodiment specifically includes information downloaded fromthe Internet and/or other networks. Such signal-bearing media, whencarrying computer-readable instructions that direct the functions of thepresent invention, represent a part of embodiments of the presentinvention. In general, routines executed to implement the embodiments ofthe invention may be part of an operating system or a specificapplication, component, program, module, object, or sequence ofinstructions. Software disclosed may comprise variables and datastructures that either reside locally to the program or are found inmemory or on storage devices.

Each of the processes, methods, and algorithms described herein may beembodied in, and fully or partially automated by, code instructionsexecuted by one or more computing devices or computer processorscomprising computer hardware. The processes and algorithms may beimplemented partially or wholly in application-specific circuitry.

Some actions described herein may be automated to a greater or lesserextent, according to algorithms and/or preset operator preferences.Therefore, it is to be understood that where an action is shown ordescribed as being performed by an operator, in various implementationsand/or circumstances the action may be performed entirely by the sortercontrol computer or sort module controller(s) or by the operator, usingthe sorter control computer or another computing device to a greater orlesser extent (e.g. a user may type out instructions, or may choose frompreselected options generated by the control computer). Similarly, wherean action is shown or described as being carried out by the sortercontrol computer and/or a controller, the action may be performedautonomously by that computing device or with more or less user input,in various circumstances and implementations.

It is to be understood that the sorter control computer can beimplemented in various known ways in different embodiments of theinvention. For example, the sorter control computer may be implementedas any kind of computing device, in a single device or distributed overmultiple devices (including a cloud). The sorter control computer may beprimarily remote or primarily local, and may be interfaced primarilylocally via inputs such as keyboard and display, or primarily remotelyvia an app or other software. The sorter control computer, and any partthereof, may be placed at any position, near or far from the inductionsubsystem and sort modules. The sorter control computer may havemultiple local interfaces (e.g. keyboard, mouse, display) at differentphysical locations, may have both local and remote access points, etc.

The sortation sub-system is formed by a series of sort modules that arephysically connected together end-to-end. Each sort module has aconveying surface with a method to convey the product to the next sortmodule, and another method to transfer the product off of the sortmodule and to the right or left to sort the package into a waitingcontainer or package transport device. A package transport device may bea conveyor, skate wheel, or any other known material handling transportdevice, or even another sort module. In some embodiments sort modulesmay be positioned side to side, although generally not in the mosttypical implementations. In many applications, a package sorted off asort module to the left or right is out of the sort module system onceexiting off the side of the sort module. Each sort module has its ownPLC that provides local control for the mechanical operation of the sortmodule and communicates with both the neighboring upstream anddownstream sort module PLCs. The same PLCs also communicate with thesorter control computer located in the induction sub-system under aseparate protocol to provide status information about each module andrelay operator inputs from touch buttons and indicator lamps.

In some embodiments touch buttons and indicator lamps are combined in atouch lamp button which may be essentially a push button with anintegrated LED or other light. Lights may be used to indicate issues atthat section of the sorter, for example a slow flash for a containergetting full, a fast flash if a jam is detected and the sorter stoppedas a result. Any known indicator lights can be used and, for example,information may be conveyed based on the color of light as well aswhether the light is flashing or solid and if flashing, the frequency.The buttons are input devices for the operator(s), typically a simplepush button may be pushed to take the associated sort point offline inorder to change the container used to receive packages at that sortpoint, and pressed again to put that sort point back in service and turnoff the (for example) slow flashing light that was indicating acontainer approaching full capacity. Use of the button may be similarfor a jam in which the sort module has been stopped. The material thatis jammed may be poked out of the way by an operator, who then touchesthe button to indicate clearance of the jam and resume operations of thesort module. In a typical embodiment, operators can control individuallocal sort modules directly with their associated buttons, or remotelyfrom the sorter control computer, such that there is a mixedlocal-global control architecture. Each sort module's PLC controls thesame sort module's buttons/lights, but an operator may send a messagefrom the sorter control computer to the local PLC to turn off the light,restart the module, etc. and the PLC similarly, if the buttons areoperated locally, will relay that back to the sorter control computer.

The data set prepared by the sorter control computer is communicated tothe first PLC of the sort modules as the package enters the sortersub-system. Typically, entry of the package into the sorter sub-systemis determined using though-beam array sensors located before each sortmodule as described in detail below. These sensors detect each packageas it proceeds onto the sort module, and can determine the leading andtrailing edge of each package and when the edges cross the through-beamarray. Speed of the conveyors, and therefore packages, is known frommotor encoders, although the through-beam array may also be used todetermine speed of the package. Package speed may assist with, forexample, discharge from the sort module to sort points. For example,package length and module length may be used to determine whetherpackage speed should be adjusted to improve discharge reliability and/orreduce jam risk, as described in more detail below. The PLC in each sortmodule receives the data set for the incoming package from its upstreamneighbor. Based on the data, the PLC will execute the program to passthe package to the next sort module, or discharge the package to rightor left side sort points. If the package sort point destination isfurther down the sorter, the data set will be sent to the nextdownstream module PLC and the process will repeat itself until thepackage reaches its intended sort point destination. In manyembodiments, all sort modules are identical, and each has its own PLC,set of sensors, indicators, pushbuttons, and motors (for example asdescribed in detail herein). Identical sort modules allow for veryefficient manufacturing and low cost, while retaining flexibility. Forexample, depending on space constraints it might be desired for thesorting sub-system to make a turn, which can be accomplished for exampleby inserting a “pie-slice” roller or conveyor section in-between sortmodules. In some embodiments, the sort modules may be identical exceptfor size, and for example smaller sort modules might be used inparticular locations such as at the end of the sorting sub-system tobetter handle smaller packages. In general, sort module size may beselected based on the objects to be sorted. A local power supply may beconnected to the overall power distribution system and able to providelocal DC power to one or several modules.

The common design and construction of the sort modules lowersmanufacturing costs since all modules are the same, regardless of thesorter size. The distributed control architecture allows each sortmodule to be self-controlled and includes a standard protocol forcommunication to adjacent modules, handing off packages between modules,and status communications with the sorter control computer. Adding orsubtracting additional modules does not affect the other modules or thesorter control software, and only requires a change in configurationsettings.

The common PLC program that is installed in each of the sort modulesincludes many adaptive subroutines that can be activated by the data setassociated with each package. These adaptive features increase theoverall performance and reliability of the sorter system. Non-limitingexamples include: how the timing or speed of the sort module functionsis changed based on the length of the package; and how the transportspeed of a sort module may be changed based on the sort pointdestination and anticipation of desired operation in the next downstreamsort module.

The speed of each sort module can be controlled by its respective PLC.To reduce jams, when a large package is identified that might bedifficult to discharge to either side or stop within a single module dueto its momentum and sliding, the transport speed of the module thatpackage is on may be slowed down without slowing down the other modules,allowing for reliable transfer. In embodiments, if a package slides toofar and crosses a through-beam array (or other) sensor between moduleswhen it was supposed to have been discharged to either side or stopped,the system notes an unexpected package and signals a jam. By slowingdown the sort module prior to the module where the large package is tobe sorted out of the system, the system can reduce the chances of thepackage sliding past its intended sort point to a subsequent module,which would cause a jam and in most implementations require manualprocessing of the package to get it back on track to its sort point.This is a very important feature of a modular system which makes it farmore reliable than a conventional single-conveyor system in which theentire system is driven at the same speed all the time.

Note that the package length can be calculated from the time betweenleading edge and trailing edge detection by a through-beam array or byimaging or other data capture in the induction sub-system. In someembodiments, package weight, for example gathered in the inductionsub-system, may also be used to trigger a slowing of sort moduletransport speed. In any event, length of a package relative to length ofa sort module is a very important factor, since it determines the amountof travel distance a package has before it will extend off the end ofthe sort module.

Parameters for when sort modules are slowed and to what speed may bepre-set based on characteristics of a given system and/or objects to besorted, but may also adapt over time using known AI techniques. Jams andtheir locations are logged and where jam frequency is relatively high,sort modules speeds are reduced to test whether that reduces the jamfrequency. If reducing speed is found to reduce the number of jams,speed may be slowly decreased until e.g., jam frequency is within 10% ofthe system average, or overall throughput is maximized (i.e. if below acertain speed the number of objects being successfully sorted per unittime goes down, speed is increased again to find the optimum). By way ofexample, if furniture varnish spills on one sort module and reduces thecoefficient of friction of the conveyor surface, that sort module willexperience a higher frequency of jams which the system will identify,reduce the speed of the sort module and bring the jam percentage back inline with the other sort modules. This is a large improvement overconventional sorting systems with single speeds.

In some embodiments, each sort module starts when the sensor located inthe gap immediately before the module detects the leading edge of apackage. Packages will pass over a sort module without stopping if notbeing sorted off the side to their sort point destination from that sortmodule and if the next sort module is clear and ready to accept the nextpackage. The sort module will continue to run and transport the packageto the downstream sort module and stop running when the sensor at thebeginning of the downstream sort module sees the trailing edge of thepackage.

However, if the next module is not clear, the package will have to stopbefore entering the next module. In this case the first sort module willstart as before when the entrance sensor detects the leading edge of apackage. However, the sort module must stop the package before blockingthe entrance sensor of the downstream sort module. To stop the packagein time, the same sensor that detects the leading edge of the package isalso used to detect the trailing edge of the package and signal the sortmodule to stop.

The available stopping distance is a function of the length of thepackage and the length of the sort module. For example, if the sortmodule is 40 inches long, and transporting a 10 inch package at 40inches per second, the package will have 30 inches, or ¾ seconds beforeit is at the end of the sort module and is detected by the entrancesensor to the next sort module. Based on package types, ¾ of a second,or 30 inches, may be sufficient time for a 10 inch long package to bestopped.

Larger packages decrease the available stopping distances and timesunless compensations are made. As an example, if the same sort module is40 inches long, and transporting a 20 inch package at 40 inches persecond, this package will only have 20 inches, or ½ second to stop afterthe trailing edge clears the entrance sensor. This may not be enoughtime or distance for the package to be stopped, if it is required to bestopped, before moving to the next sort module. Insufficient stoppingdistances and times will cause excessive jams, decreasing the overallthroughput of the sorter.

Rather than slow down the overall sorter, adaptive features of theprogram running on the PLCs of the sort modules may be used to slow thetransport speed of the sort module only when needed for a largerpackage. In this example, the PLC of the sort module knows that thepackage is 20 inches long (as determined at induction of the packageand/or by the sensors). Based on pre-programmed values, or machinelearning, the PLC knows 40 in/s is too fast for a desired operatingreliability. The PLC therefore slows the transport speed of the moduleto 20 inches per second, giving the 20 inch package 20 inches or a full1 second to come to a stop, if it is required to be stopped beforemoving to the next sort module. A slower transport speed for largepackages also increases the reliability of diversion of large packagesoff the sorter at the sort point destination module.

The ability to dynamically adjust the speed of a sort module based onthe size of the package is an adaptive control feature that allows thesorter to run at a maximum speed and throughput for most packages, yetslow down when required for larger packages to avoid jams and increasereliability

Other features in the PLC program common to all sort modules may includethe ability to detect jammed packages or lost packages and communicatestatus information between the individual sort modules and thesupervisory sort computer.

In normal operation, since a PLC will not give the go-ahead to theprevious sort module until its conveyor surface is clear, no more thanhalf of the sort modules will have a package at any given time (althoughin case of a jam that stops a sort module and creates a backup behindthe jammed sort module, packages may “line up” behind the stopped sortmodule, with a package on every sort module), and no more than half ofthe sort module conveyor surfaces will be operating at any given time(at least in a non-discharge direction). As a direct consequence, thesorter in such embodiments generates at most only half the noise of anon-modular sorter, and wear-and-tear on sorter transport surfaces andmechanical systems is significantly reduced. As many as half the sortmodule conveyor surfaces would be running only in very high-volumesituations (and often not even then), which are relatively rare in mostsorter implementations (or in rare “purge” scenarios described below, inwhich more than half the sort module conveyor surfaces may run at anyone time). At other times, significantly less than half of sort moduleconveyor surfaces would be running at any one time. For example, anoperator may throw a few packages on the sort system, go back and grab afew more packages and throw them on, etc. In such scenarios, only a fewsort module conveyor surfaces may be running at any one time. Sortmodules towards the end of a linear sort system in particular see verylow volumes and run very rarely. As such, noise and wear-and-tear arereduced by much more than half in most operational situations, ascompared to sort systems with a single long (non-modular) conveyorsurface.

Note that this control rule of stopping a sort module conveyor surfacewhen the next downstream sort module is not clear is a very simple rulethat results in high reliability with the modular sort system. However,in other embodiments a higher throughput may be achieved for high volumesorting by relaxing the rule of stopping packages until the next sortmodule is clear. For example, where a package on the next downstreamsort module has a leading edge that has been detected passing the sensorjust after the next downstream sort module (i.e. before the subsequentdownstream sort module after the next downstream sort module), it mightbe anticipated that package will shortly clear the next downstream sortmodule and pass fully onto the subsequent downstream sort module. Assuch, a package may not be stopped, but rather the sort module maycontinue to run and allow the package to proceed on to the nextdownstream sort module based on the anticipation that the packagethereon will exit that next downstream sort module soon. Such logic maybe implemented in some embodiments only when a high volume of packagesis detected, and/or when reliability is not expected to be adverselyaffected, at least beyond a certain threshold level.

According to at least some embodiments, a modular package sorting systemis disclosed herein, the system comprising a plurality of sort modulesconfigured to convey a package to one of a plurality of sortation pointscorresponding to a sort point destination of the package; and adistributed control architecture comprising a plurality of controllers,each of the plurality of controllers being associated with one sortmodule in the plurality of sort modules, each of the plurality ofcontrollers is configured to communicate with one or more othercontrollers in the plurality of controllers, including to receive andtransmit an electronic packet of data, and to determine, usinginformation contained in the electronic packet of data, whether toconvey the package from the associated one sort module to a subsequentsort module or to a sortation point associated with the one sort module,based on the sort point destination for the package, the electronicpacket of data includes the sort point destination for the package, andeach of the plurality of controllers is capable of controlling itsrespective sort module.

The modular package sorting system, in some of the aforementioned atleast some embodiments, further comprises an induction subsystemconfigured to initially receive the package and transport it to theplurality of sort modules, the induction subsystem is configured not totransport the package to the plurality of sort modules until informationis successfully read from a label of the package.

The induction subsystem may additionally be configured to obtaininformation regarding the received package, to determine the sort pointdestination for the received package based on the obtained information,and to transmit the sort point destination to the plurality of sortmodules.

Such information regarding the received package may comprise addressinformation, dimensions, and weight.

The induction subsystem may also be configured to transmit the sortpoint destination to a first controller of the plurality of controllersassociated with a first sort module of the plurality of sort modules, towhich the package is conveyed from the induction sub-system.

In some of the aforementioned at least some embodiments of the modularpackage sorting system, each of the plurality of controllers isconfigured to communicate with a subsequent controller of the pluralityof controllers, and each of the subsequent controllers is associatedwith an immediately subsequent sort module of the plurality of sortmodules to which the controller is configured to convey the package viathe sort module associated with the controller, and to transmit to thesubsequent controller the sort point destination.

The plurality of sort modules in some of the aforementioned at leastsome embodiments may be rearranged in any order while maintaining theability of each controller to communicate with the subsequent controllerassociated with the sort module to which its associated sort module isconfigured to convey the package, even though an identity of thesubsequent controller changes due to the rearrangement.

Further, the induction subsystem may also comprise conveyor componentscontrolled by a sorter control computer configured to move the packagethrough a series of stations and collect the information regarding thereceived package.

In some of the aforementioned at least some embodiments, each of theplurality of controllers is capable of controlling its respective sortmodule independently of the sorter control computer.

The induction subsystem in some of the aforementioned at least someembodiments of the modular package sorting system may be configured todetermine the sort point destination based at least in part on theaddress information, package dimensions, and/or weight.

The induction subsystem may additionally comprise an imaging device, adimensioner, and a weighing system, the induction sub-system isconfigured to read a barcode of the package with the imaging device and,when the barcode cannot be read, to halt induction of the package untilthe barcode is read successfully or necessary information is inputmanually, the induction sub-system is configured to halt induction ofthe package and clear the obtained information regarding the receivedpackage responsive to an input instruction.

Additionally, some of the aforementioned at least some embodiments ofthe modular package sorting system comprise a sorter control computerconfigured to determine the sort point destination based on theinformation regarding the received package. Such a sorter controlcomputer may be configured to communicate with the plurality ofcontrollers.

In some of the aforementioned at least some embodiments, the sortercontrol computer is configured to keep track of a volume of packagessorted to each of the plurality of sortation points based on dimensionalinformation of packages determined to have each sort point as their sortpoint destination, comparing the volume of packages to a capacity ofeach of the plurality of sortation points, and providing notificationwhen a particular sortation point is determined to be within a thresholdpercentage of its capacity.

The sorter control computer may additionally be configured to logerrors, report error rates and error locations, and route around and/orreduce speed of sort modules experiencing errors.

In some of the aforementioned at least some embodiments, the pluralityof sort modules comprises a series of sort modules physically connectedtogether end-to-end and being configured to convey items from the firstsort module to a last sort module over the series of sort modules, andthe controller associated with each sort module is configured tocommunicate with controllers associated with sort modules just beforeand just after in the series, when they exist.

Further, each controller of the plurality of controllers is programmedto carry out an identical operation, the operation comprising receivingthe sort point destination from an induction subsystem or from acontroller of an immediately preceding sort module, using the sort pointdestination to determine whether to move the package off the side of theassociated sort module to a sort point or to convey the package to animmediately subsequent sort module, and, when conveying the package tothe immediately subsequent sort module, transmitting the sort pointdestination to the controller associated with the immediately subsequentsort module.

In some of the aforementioned at least some embodiments, each of theplurality of sort modules comprises a conveyor surface configured tomove items on the conveyor surface forwards and to either side.

The conveyor surface may further comprise a transport actuatorconfigured to move items on the conveyor surface forwards and backwards,and a second transfer actuator configured to move items on the conveyorsurface to either side.

In some of the aforementioned at least some embodiments of the modularpackage sorting system, each controller is configured to controlmechanical operation of the conveyor surface of the corresponding sortmodule, the plurality of sort point destinations is located to one ormore sides of the plurality of sort modules and the plurality of sortmodules are configured to deliver packages to the sort pointdestinations by conveying them to the one or more sides of the sortmodules.

Each controller may be further programmed to reduce speed of theconveyor surface of the corresponding sort module when an item on theconveyor surface of the corresponding sort module exceeds a dimensionaland/or weight threshold.

Each controller may further be programmed to reduce speed of theconveyor surface of the corresponding sort module when an item on theconveyor surface of the corresponding sort module exceeds a dimensionaland/or weight threshold and has a sort point destination locatedadjacent to an immediately subsequent sort module. In some embodiments,a determination may be made as to whether the conveyor surface should beslowed down, in order to maximize throughput of the system based on atrade-off between increased reliability and reduced speed. Reduced speedwill tend to reduce overall throughput when volume in the system ishigh, as other packages are delayed waiting for a package on asubsequent sort module to be discharged or moved to the following sortmodule. However, this loss can be offset by increased reliability if thereduced speed lowers the probability of a jam or other error that canresult in reduced throughput. The slow-down determination may be made onthe basis of, for example, package characteristics (for exampledimensions, weight, and/or material), conveyor characteristics (such asmaterial), system speed, and/or system package volume. The determinationof when and/or how to slow down a package may be made during induction,for example by the sorter control computer, and this determination maybe included in electronic data associated with the package which isconveyed along with the package from one PLC to the next as the packageis conveyed across the sort modules. Alternatively, this determinationcould be made or adjusted by each individual PLC as the electronic datafor the package is received, for example the determination could beupdated to incorporate any changed conditions since the package wasinducted, for example if the overall system speed or system packagevolume has changed. In some embodiments the sorter control computer mayuse actual reliability information, in combination with historicalinformation regarding the determinations made as to whether to slow eachpackage and when/how, to update its estimate of the effect of suchdeterminations on system reliability, and thereby improve the accuracyof its determinations in achieving an optimal throughput.

Additionally, each controller of the plurality of controllers may beprogrammed to increase speed of the conveyor surface of thecorresponding sort module when an item on the conveyor surface of thecorresponding sort module has a sort point destination located beyond animmediately subsequent sort module and a pre-determined number ofsubsequent sort modules have no items on their respective conveyorsurfaces.

Each controller may further be configured to provide status informationabout the associated sort module.

In some of the aforementioned at least some embodiments of the modularpackage sorting system, the system comprises sensors configured to trackmovement of the package across the sort modules, the sensors compriseproximity sensors, through-beam sensors, ultrasonic sensors, and/orreflective sensors.

The sensors may comprise a plurality of angled through-beam arraysensors, and each of the plurality of angled through-beam array sensorscomprises: a light beam array comprising a plurality of individual lightbeams, at least one of the plurality of individual light beams beingdiagonal relative to a conveyor surface; an emitter; and a receiver.

The sensors may further comprise sensors between sort modules todetermine when items pass from one sort module to another, each suchsensor being associated with the controller associated with the sortmodule before or after the sensor, the controller associated with thesensor is configured to report a jam and/or stop the associated sortmodule when the associated sensor does not sense an item when expectedbecause of communication received by the controller associated with thesensor or when the associated sensor senses the item for longer than apre-determined amount of time.

In some of the aforementioned at least some embodiments of the modularpackage sorting system, the plurality of controllers is configured todetermine, before moving each package from one sort module to a nextsort module, whether another package is located on the next sort moduleand, if so, waiting to move the package onto the next sort module untilthe other package is no longer located on the next sort module. Each ofthe plurality of controllers has its own rule set.

Additionally, in some of the aforementioned at least some embodiments,the distributed control architecture is configured to distribute controlof the plurality of sort modules among the plurality of controllers.

Further, in some of the aforementioned at least some embodiments, theelectronic packet of data comprises information relating to physicaldimensions of the package.

Each of the plurality of controllers may also be configured to receivethe electronic packet of data from an immediately preceding controllerin a sequence, and subsequently to convey the electronic packet of datato an immediately succeeding controller in the sequence.In some of the aforementioned at least some embodiments, thetransmission of the electronic packet of data occurs at the same time asthe conveyance of the package from the associated one sort module to thesubsequent sort module or to the sortation point associated with the onesort module.

The electronic packet of data may further comprise informationidentifying the package and/or the package's dimensions and/or thepackage's weight.

In some of the aforementioned at least some embodiments of the modularpackage sorting system, each of the plurality of controllers is furtherconfigured to determine a speed among a plurality of speeds at which tosend the package to the subsequent sort module. The plurality of speedsis pre-installed on each of the plurality of controllers.

The aforementioned speed determination may depend at least on whetherthe package is to be discharged to a sortation point associated with thesubsequent sort module.

The speed determination may additionally depend at least on whether thepackage is to be discharged to a sortation point associated with a sortmodule downstream of the subsequent sort module. The determining of thespeed may further depend at least on physical dimensions of the package

In some of the aforementioned at least some embodiments, the determinedspeed differs from a speed at which the associated one sort modulereceived the package.

Additionally, in some of the aforementioned at least some embodiments, afirst controller in the plurality of controllers is associated with afirst sort module in the plurality of sort modules, a second controllerin the plurality of controllers is associated with a second sort modulein the plurality of sort modules, a third controller in the plurality ofcontrollers is associated with a third sort module in the plurality ofsort modules, the first, second, and third sort modules being connectedin series, and the second controller is configured to receive a queryfrom the first controller as to whether the second sort module is empty,and to transmit a response to the query from the first controller whenthe second sort module is empty, and when the package received on thesecond sort module is to be transported to the third sort module,selecting a speed from among a plurality of speeds pre-installed in thesecond controller at which to send the package to the third sort module,sending a query to the third controller as to whether the third sortmodule is empty, and only sending the package to the third controllerafter having received a response from the third controller to the queryto the third controller.

Each of the plurality of controllers may further be configured forcommunication only with the controllers associated with sort modulesimmediately preceding and immediately following the associated one sortmodule, the communication including responding to a request from thecontroller associated with the immediately preceding sort module,receiving a packet of data comprising the sort point destination for thepackage from the immediately preceding sort module when the package isconveyed from the immediately preceding sort module to the associatedone sort module, sending a request to the controller associated with theimmediately following sort module when the sort point destination of thepackage is not the sortation point associated with the one sort module,and sending the packet of data to the immediately following sort modulewhen conveying the package to the immediately following sort module.

In some of the aforementioned at least some embodiments, the modularpackage sorting system further comprises a second plurality of sortmodules, each of the second plurality of sort modules having only animmediately preceding sort module or an immediately following sortmodule, but not both, such immediately preceding sort module orimmediately following sort module being one of the plurality of sortmodules.

In one or more further embodiments, the modular package sorting systemcomprises a plurality of sort modules configured to convey a package toone of a plurality of sortation points corresponding to a sort pointdestination of the package, and a distributed control architecturecomprising a plurality of controllers, each of the plurality ofcontrollers being associated with one sort module in the plurality ofsort modules, each of the plurality of controllers is configured tocommunicate with one or more other controllers in the plurality ofcontrollers and to determine whether to convey the package from theassociated one sort module to a subsequent sort module or to a sortationpoint associated with the one sort module, based on the sort pointdestination for the package, and each of the plurality of controllers iscapable of controlling its respective sort module. The package sortingsystem further comprises an induction subsystem configured to initiallyreceive the package and transport it to the plurality of sort modules,the induction subsystem is configured not to transport the package tothe plurality of sort modules until information is successfully readfrom a label of the package, the induction subsystem is configured toobtain information regarding the received package, to determine the sortpoint destination for the received package based on the obtainedinformation, and to transmit the sort point destination to the pluralityof sort modules. The package sorting system further comprises a sortercontrol computer configured to determine the sort point destinationbased on the information regarding the received package, the sortercontrol computer is configured to take away control of two or more ofthe sort modules from the controllers and run the two or more sortmodules together to purge the two or more sort modules of packages,responsive to a jam being detected and/or to user input.

In the aforementioned one or more such embodiments of the modularpackage sorting system, the sorter control computer may be configured toleave one or more other of the sort modules under control of theircontrollers when taking control of the two or more sort modules.

A modular package sorting system according to various embodimentscomprises a plurality of sort modules configured to convey a package toone of a plurality of sortation points corresponding to a sort pointdestination of the package and comprising a plurality of controllers,each of the plurality of controllers being associated with one sortmodule in the plurality of sort modules, each of the plurality ofcontrollers is configured to communicate with one or more othercontrollers in the plurality of controllers and to determine whether toconvey the package from the associated one sort module to a subsequentsort module or to a sortation point associated with the one sort module,based on the sort point destination for the package, and each of theplurality of controllers is configured to receive a request for a firstready message, transmit the first ready message when the correspondingsort module is determined to be empty, determine whether a packagereceived on the corresponding sort module is to be discharged to a rightor left sort direction or transported to another sort module, and whenthe package received on the corresponding sort module is to betransported to another sort module, sending a request for a second readymessage to the controller corresponding to the another sort module,receiving the second ready message from the controller corresponding tothe another sort module, and sending the package received on thecorresponding sort module to the another sort module, responsive toreceipt of the second ready message from the controller corresponding tothe another sort module.

In at least further embodiments of the modular package sorting system,the system comprises a plurality of self-controlled sort modulesconfigured to convey a package to a one of a plurality of sortationpoints, and comprising a plurality of controllers, each of the pluralityof controllers being associated with one sort module in the plurality ofsort modules, each of the plurality of controllers is configured todetermine, when the package is received on the corresponding sortmodule, whether to convey the package to a subsequent sort module or toa sortation point associated with the corresponding sort module, and,when the package is to be conveyed to the subsequent sort module, isconfigured to communicate with the controller associated with thesubsequent sort module by transmitting a request for a ready message tothe controller corresponding to the subsequent sort module and byreceiving the ready message from the controller corresponding to thesubsequent sort module, and to send the package to the subsequent sortmodule after receipt of the ready message from the controllercorresponding to the subsequent sort module.

In some of the aforementioned at least further embodiments, the messagereceived from the controller associated with the subsequent sort moduleindicates that the subsequent sort module is ready to receive thepackage.

Each of the plurality of controllers may further be configured to enablethe self-control of its respective sort module.

In some of the at least further embodiments, each of the plurality ofcontrollers comprises an identical standard protocol for communicatingwith sort modules adjacent to the associated one sort module. Thisstandard protocol is configured to enable the sending of the package tothe subsequent sort module.

Additionally, each of the plurality of controllers may be autonomousfrom a central operator supervisory control.

In some of the at least further embodiments of the modular packagesorting system, the plurality of sort modules comprises a series of sortmodules physically connected together end-to-end and being configured toconvey items from a first sort module to a last sort module over theseries of sort modules, and the controller associated with each sortmodule is configured to communicate with controllers associated withsort modules just before and just after in the series, when they exist.

Additionally, each controller of the plurality of controllers isprogrammed to carry out an identical operation, the operation comprisingreceiving a sort point destination from an induction subsystem or from acontroller of an immediately preceding sort module, using the sort pointdestination to determine whether to move the package off to a side ofthe corresponding sort module to the sortation point associated with thecorresponding sort module or to convey the package to an immediatelysubsequent sort module, and, when conveying the package to theimmediately subsequent sort module, transmitting the sort pointdestination to the controller associated with the immediately subsequentsort module.

Each of the plurality of sort modules may additionally comprise aconveyor surface configured to move items on the conveyor surfaceforwards and to either side.

The conveyor surface comprises a transport actuator configured to moveitems on the conveyor surface forwards and backwards, and a secondtransfer actuator configured to move items on the conveyor surface toeither side.

In some of the at least further embodiments, each controller isconfigured to control mechanical operation of the conveyor surface ofthe corresponding sort module, the plurality of sort point destinationsis located to one or more sides of the plurality of sort modules and theplurality of sort modules are configured to deliver packages to sortpoint destinations by conveying them to the one or more sides of thesort modules.

Each controller of the plurality of controllers may be programmed toreduce speed of the conveyor surface of the corresponding sort modulewhen an item on the conveyor surface of the corresponding sort moduleexceeds a dimensional and/or weight threshold.

Each controller of the plurality of controllers may further beprogrammed to reduce speed of the conveyor surface of the correspondingsort module when an item on the conveyor surface of the correspondingsort module has a sort point destination located adjacent to animmediately subsequent sort module.

Each controller of the plurality of controllers may additionally beprogrammed to increase speed of the conveyor surface of thecorresponding sort module when an item on the conveyor surface of thecorresponding sort module has a sort point destination located beyond animmediately subsequent sort module and a pre-determined number ofsubsequent sort modules have no items on their respective conveyorsurfaces.

Each controller may further be configured to provide status informationabout the corresponding sort module.

In some of the at least further embodiments of the modular packagesorting system, the system comprises sensors configured to trackmovement of the package across the sort modules, the sensors compriseproximity sensors, through-beam sensors, ultrasonic sensors, and/orreflective sensors.

The sensors comprise a plurality of angled through-beam array sensors,and each of the plurality of angled through-beam array sensorscomprises: a light beam array comprising a plurality of individual lightbeams, at least one of the plurality of individual light beams beingdiagonal relative to a conveyor surface; an emitter; and a receiver.

The sensors may further comprise sensors between sort modules todetermine when items pass from one sort module to another, each suchsensor being associated with the controller associated with the sortmodule before or after the sensor, the controller associated with thesensor is configured to report a jam and/or stop the associated sortmodule when the associated sensor does not sense an item when expectedbecause of communication received by the controller associated with thesensor or when the associated sensor senses the item for longer than apre-determined amount of time.

In some of the at least further embodiments of the modular packagesorting system, the plurality of controllers is configured to determine,before moving each package from one sort module to a next sort module,whether another package is located on the next sort module and, if so,waiting to move the package onto the next sort module until the otherpackage is no longer located on the next sort module.

In some aspects of the invention, the controller associated with a givensort module only sends messages to the controller associated with apreceding sort module. Thus, for instance, the first ready message issent only from the controller of the corresponding sort module to thecontroller of the associated one sort module. Further, the second readymessage is sent only from the controller of the another sort module tothe controller of the corresponding sort module.

In further aspects, the controller associated with a given sort moduleonly receives messages from the controller associated with a succeedingsort module. Thus, for instance, the first ready message is received bythe controller of the associated one sort module only from thecontroller of the corresponding sort module. Further, the second readymessage is received by the controller of the corresponding sort moduleonly from the controller of the another sort module.

In various embodiments of the modular package sorting system, the systemcomprises a plurality of sort modules configured to convey a package toone of a plurality of sortation points corresponding to a sort pointdestination of the package and comprising a plurality of controllers,each of the plurality of controllers being associated with one sortmodule in the plurality of sort modules, each of the plurality ofcontrollers being configured to communicate with one or more othercontrollers in the plurality of controllers and to determine whether toconvey the package from the associated one sort module to a subsequentsort module or to a sortation point associated with the one sort module,based on the sort point destination for the package.

In some of the aforementioned various embodiments, the modular packagesorting system further comprises an induction subsystem configured toinitially receive the package and transport it to the plurality of sortmodules, the induction subsystem being configured not to transport thepackage to the plurality of sort modules until information issuccessfully read from a label of the package.

The induction subsystem may further be configured to obtain informationregarding the received package, to determine the sort point destinationfor the received package based on the obtained information, and totransmit the sort point destination to the plurality of sort modules.

The induction sub-system may additionally be configured to transmit thesort point destination to a first controller of the plurality ofcontrollers associated with a first sort module of the plurality of sortmodules, to which the package is conveyed from the induction sub-system.

In some of the aforementioned various embodiments, each of the pluralityof controllers is configured to communicate with a subsequent controllerof the plurality of controllers, and each of the subsequent controllersis associated with an immediately subsequent sort module of theplurality of sort modules to which the controller is configured toconvey the package via the sort module associated with the controller,and to transmit to the subsequent controller the sort point destination.

Additionally, the plurality of sort modules may be rearranged in anyorder while maintaining the ability of each controller to communicatewith the subsequent controller associated with the sort module to whichits associated sort module is configured to convey the package, eventhough an identity of the subsequent controller changes due to therearrangement.

The induction sub-system may further comprise conveyor componentscontrolled by a sorter control computer configured to move the packagethrough a series of stations and collect the information regarding thereceived package. Further, the information regarding the receivedpackage may comprise address information, dimensions, and weight.

The induction sub-system may further be configured to determine the sortpoint destination based at least in part on the address information,package dimensions, and/or weight.

In the some of the aforementioned various embodiments of the modularpackage sorting system, the induction sub-system comprises an imagingdevice, a dimensioner, and a weighing system, the induction sub-systemis configured to read a barcode of the package with the imaging deviceand, when the barcode cannot be read, to halt induction of the packageuntil the barcode is read successfully or necessary information is inputmanually, and the induction sub-system is configured to halt inductionof the package and clear the obtained information regarding the receivedpackage responsive to an input instruction.

Additionally, some of the aforementioned various embodiments of themodular package sorting system further comprise a sorter controlcomputer configured to determine the sort point destination based on theinformation regarding the received package.

The sorter control computer may also be configured to communicate withthe plurality of controllers.

Further, the sorter control computer may be configured to keep track ofa volume of packages sorted to each of the plurality of sortation pointsbased on dimensional information of packages determined to have eachsort point as their sort point destination, comparing the volume ofpackages to a capacity of each of the plurality of sortation points, andproviding notification when a particular sortation point is determinedto be within a threshold percentage of its capacity.

The sorter control computer may additionally be configured to logerrors, report error rates and error locations, and route around and/orreduce speed of sort modules experiencing errors.

The sorter control computer may further be configured to take awaycontrol of two or more of the sort modules from the controllers and runthe two or more sort modules together to purge the two or more sortmodules of packages, responsive to a jam being detected and/or to userinput.

The sorter control computer may also be configured to leave one or moreother of the sort modules under control of their controllers when takingcontrol of the two or more sort modules.

In some of the aforementioned various embodiments of the modular packagesorting system, each of the plurality of controllers is configured toreceive a request for a first ready message, transmit the first readymessage when the corresponding sort module is determined to be empty,determine whether a package received on the corresponding sort module isto be discharged to a right or left sort direction or transported toanother sort module, and when the package received on the correspondingsort module is to be transported to another sort module, send a requestfor a second ready message to the controller corresponding to theanother sort module, receive the second ready message from thecontroller corresponding to the another sort module, and send thepackage received on the corresponding sort module to the another sortmodule, responsive to receipt of the second ready message from thecontroller corresponding to the another sort module.

The plurality of sort modules may further comprise a series of sortmodules physically connected together end-to-end and being configured toconvey items from the first sort module to a last sort module over theseries of sort modules, and the controller associated with each sortmodule is configured to communicate with controllers associated withsort modules just before and just after in the series, when they exist.

Additionally, each controller of the plurality of controllers may beprogrammed to carry out an identical operation, the operation comprisingreceiving the sort point destination from an induction subsystem or froma controller of an immediately preceding sort module, using the sortpoint destination to determine whether to move the package off the sideof the associated sort module to a sort point or to convey the packageto an immediately subsequent sort module, and, when conveying thepackage to the immediately subsequent sort module, transmitting the sortpoint destination to the controller associated with the immediatelysubsequent sort module.

In some of the aforementioned various embodiments of the modular packagesorting system, each of the plurality of sort modules comprises aconveyor surface configured to move items on the conveyor surfaceforwards and to either side.

The conveyor surface may comprise a transport actuator configured tomove items on the conveyor surface forwards and backwards, and a secondtransfer actuator configured to move items on the conveyor surface toeither side.

Further, each controller may be configured to control mechanicaloperation of the conveyor surface of the corresponding sort module, andthe plurality of sort point destinations may be located to one or moresides of the plurality of sort modules and the plurality of sort modulesmay be configured to deliver packages to the sort point destinations byconveying them to the one or more sides of the sort modules.

Each controller of the plurality of controllers may be programmed toreduce speed of the conveyor surface of the corresponding sort modulewhen an item on the conveyor surface of the corresponding sort moduleexceeds a dimensional and/or weight threshold.

Each controller of the plurality of controllers may further beprogrammed to reduce speed of the conveyor surface of the correspondingsort module when an item on the conveyor surface of the correspondingsort module has a sort point destination located adjacent to animmediately subsequent sort module.

Each controller of the plurality of controllers may additionally beprogrammed to increase speed of the conveyor surface of thecorresponding sort module when an item on the conveyor surface of thecorresponding sort module has a sort point destination located beyond animmediately subsequent sort module and a pre-determined number ofsubsequent sort modules have no items on their respective conveyorsurfaces.

Each controller may further be configured to provide status informationabout the associated sort module.

In some of the aforementioned various embodiments of the modular packagesorting system, the system further comprises sensors configured to trackmovement of the package across the sort modules, and the sensors maycomprise proximity sensors, through-beam sensors, ultrasonic sensors,and/or reflective sensors.

The sensors may comprise a plurality of angled through-beam arraysensors, and each of the plurality of angled through-beam array sensorsmay comprise: a light beam array comprising a plurality of individuallight beams, at least one of the plurality of individual light beamsbeing diagonal relative to a conveyor surface; an emitter; and areceiver.

The sensors may additionally comprise sensors between sort modules todetermine when items pass from one sort module to another, each suchsensor being associated with the controller associated with the sortmodule before or after the sensor, the controller associated with thesensor being configured to report a jam and/or stop the associated sortmodule when the associated sensor does not sense an item when expectedbecause of communication received by the controller associated with thesensor or when the associated sensor senses the item for longer than apre-determined amount of time.

In some of the various aforementioned embodiments of the modular packagesorting system, the plurality of controllers are configured todetermine, before moving each package from one sort module to a nextsort module, whether another package is located on the next a sortmodule and, if so, waiting to move the package onto the next sort moduleuntil the other package is no longer located on the next sort module.

Therefore, based on the foregoing and continuing description, thesubject invention in its various embodiments may comprise one or more ofthe following features in any non-mutually-exclusive combination:

-   -   A modular package sorting system including a plurality of sort        modules configured to convey a package to one of a plurality of        sortation points corresponding to a sort point destination of        the package, and a distributed control architecture comprising a        plurality of controllers, each of the plurality of controllers        being associated with one sort module in the plurality of sort        modules;    -   Each of the plurality of controllers of a modular package        sorting system being configured to communicate with one or more        other controllers in the plurality of controllers, including to        receive and transmit an electronic packet of data, and to        determine, using information contained in the electronic packet        of data, whether to convey the package from the associated one        sort module to a subsequent sort module or to a sortation point        associated with the one sort module, based on the sort point        destination for the package;    -   Each of the plurality of controllers of a modular package        sorting system being capable of controlling its respective sort        module;    -   Each of the plurality of controllers of a modular package        sorting system being configured to communicate with a subsequent        controller of the plurality of controllers, and each of the        subsequent controllers being associated with an immediately        subsequent sort module of the plurality of sort modules to which        the controller is configured to convey the package via the sort        module associated with the controller, and to transmit to the        subsequent controller the sort point destination;    -   The electronic packet of data received and transmitted by the        plurality of controllers includes the sort point destination for        the package;    -   The electronic packet of data further comprises information        relating to physical dimensions of the package;    -   The distributed control architecture is configured to distribute        control of the plurality of sort modules among the plurality of        controllers;    -   A modular package sorting system including an induction        subsystem configured to initially receive the package and        transport it to the plurality of sort modules, wherein the        induction subsystem is configured not to transport the package        to the plurality of sort modules until information is        successfully read from a label of the package;    -   The induction subsystem being configured to obtain information        regarding the received package, to determine the sort point        destination for the received package based on the obtained        information, and to transmit the sort point destination to the        plurality of sort modules;    -   The induction subsystem being configured to transmit the sort        point destination to a first controller of the plurality of        controllers associated with a first sort module of the plurality        of sort modules, to which the package is conveyed from the        induction sub-system;    -   The induction subsystem being configured to determine the sort        point destination based at least in part on the address        information, package dimensions, and/or weight;    -   The induction subsystem comprising conveyor components        controlled by a sorter control computer configured to move the        package through a series of stations and collect the information        regarding the received package;    -   The information regarding the received package comprising        address information, dimensions, and weight;    -   The induction subsystem further comprising an imaging device, a        dimensioner, and a weighing system, the induction sub-system        being configured to read a barcode of the package with the        imaging device and, when the barcode cannot be read, to halt        induction of the package until the barcode is read successfully        or necessary information is input manually, the induction        sub-system being configured to halt induction of the package and        clear the obtained information regarding the received package        responsive to an input instruction;    -   The plurality of sort modules in a modular package sorting        system may be rearranged in any order while maintaining the        ability of each controller to communicate with the subsequent        controller associated with the sort module to which its        associated sort module is configured to convey the package, even        though an identity of the subsequent controller changes due to        the rearrangement;    -   A modular package sorting system including a sorter control        computer configured to determine the sort point destination        based on the information regarding the received package;    -   The sorter control computer can be configured to communicate        with the plurality of controllers;    -   The sorter control computer can further be configured to keep        track of a volume of packages sorted to each of the plurality of        sortation points based on dimensional information of packages        determined to have each sort point as their sort point        destination, comparing the volume of packages to a capacity of        each of the plurality of sortation points, and providing        notification when a particular sortation point is determined to        be within a threshold percentage of its capacity;    -   The sorter control computer can additionally be configured to        log errors, report error rates and error locations, and route        around and/or reduce speed of sort modules experiencing errors;    -   A modular package sorting system including a plurality of sort        modules configured to convey a package to one of a plurality of        sortation points corresponding to a sort point destination of        the package, and a distributed control architecture comprising a        plurality of controllers, each of the plurality of controllers        being associated with one sort module in the plurality of sort        modules, wherein each of the plurality of controllers is        configured to communicate with one or more other controllers in        the plurality of controllers and to determine whether to convey        the package from the associated one sort module to a subsequent        sort module or to a sortation point associated with the one sort        module, based on the sort point destination for the package, and        wherein each of the plurality of controllers is capable of        controlling its respective sort module;    -   The modular package sorting system further includes an induction        subsystem configured to initially receive the package and        transport it to the plurality of sort modules, the induction        subsystem is configured not to transport the package to the        plurality of sort modules until information is successfully read        from a label of the package, and the induction subsystem is        configured to obtain information regarding the received package,        to determine the sort point destination for the received package        based on the obtained information, and to transmit the sort        point destination to the plurality of sort modules;    -   The modular package sorting system further includes a sorter        control computer configured to determine the sort point        destination based on the information regarding the received        package, wherein the sorter control computer is configured to        take away control of two or more of the sort modules from the        controllers and run the two or more sort modules together to        purge the two or more sort modules of packages, responsive to a        jam being detected and/or to user input;    -   The sorter control computer of the modular package sorting        system may be configured to leave one or more other of the sort        modules under control of their controllers when taking control        of the two or more sort modules;    -   A modular package sorting system including a plurality of sort        modules configured to convey a package to one of a plurality of        sortation points corresponding to a sort point destination of        the package and comprising a plurality of controllers, each of        the plurality of controllers being associated with one sort        module in the plurality of sort modules, wherein each of the        plurality of controllers is configured to communicate with one        or more other controllers in the plurality of controllers and to        determine whether to convey the package from the associated one        sort module to a subsequent sort module or to a sortation point        associated with the one sort module, based on the sort point        destination for the package, and wherein each of the plurality        of controllers is configured to receive a request for a first        ready message, transmit the first ready message when the        corresponding sort module is determined to be empty, determine        whether a package received on the corresponding sort module is        to be discharged to a right or left sort direction or        transported to another sort module, and when the package        received on the corresponding sort module is to be transported        to another sort module, sending a request for a second ready        message to the controller corresponding to the another sort        module, receiving the second ready message from the controller        corresponding to the another sort module, and sending the        package received on the corresponding sort module to the another        sort module, responsive to receipt of the second ready message        from the controller corresponding to the another sort module;    -   The plurality of sort modules comprises a series of sort modules        physically connected together end-to-end and being configured to        convey items from the first sort module to a last sort module        over the series of sort modules, and the controller associated        with each sort module is configured to communicate with        controllers associated with sort modules just before and just        after in the series, when they exist;    -   Each controller in the plurality of controllers is programmed to        carry out an identical operation, the operation comprising        receiving the sort point destination from an induction subsystem        or from a controller of an immediately preceding sort module,        using the sort point destination to determine whether to move        the package off the side of the associated sort module to a sort        point or to convey the package to an immediately subsequent sort        module, and, when conveying the package to the immediately        subsequent sort module, transmitting the sort point destination        to the controller associated with the immediately subsequent        sort module;    -   Each of the plurality of sort modules may comprise a conveyor        surface configured to move items on the conveyor surface        forwards and to either side;    -   The conveyor surface may comprise a transport actuator        configured to move items on the conveyor surface forwards and        backwards, and a second transfer actuator configured to move        items on the conveyor surface to either side;    -   Each controller of the plurality of controllers is configured to        control mechanical operation of the conveyor surface of the        corresponding sort module, the plurality of sort point        destinations is located to one or more sides of the plurality of        sort modules and the plurality of sort modules are configured to        deliver packages to the sort point destinations by conveying        them to the one or more sides of the sort modules;    -   Each controller of the plurality of controllers is programmed to        reduce speed of the conveyor surface of the corresponding sort        module when an item on the conveyor surface of the corresponding        sort module exceeds a dimensional and/or weight threshold;    -   Each controller of the plurality of controllers is further        programmed to reduce speed of the conveyor surface of the        corresponding sort module when an item on the conveyor surface        of the corresponding sort module has a sort point destination        located adjacent to an immediately subsequent sort module;    -   Each controller of the plurality of controllers is additionally        programmed to increase speed of the conveyor surface of the        corresponding sort module when an item on the conveyor surface        of the corresponding sort module has a sort point destination        located beyond an immediately subsequent sort module and a        pre-determined number of subsequent sort modules have no items        on their respective conveyor surfaces;    -   Each controller of the plurality of controllers configured to        provide status information about the associated sort module;    -   The modular package sorting system further includes sensors        configured to track movement of the package across the sort        modules, and the sensors comprise proximity sensors,        through-beam sensors, ultrasonic sensors, and/or reflective        sensors;    -   The sensors comprise a plurality of angled through-beam array        sensors, and each of the plurality of angled through-beam array        sensors comprises a light beam array comprising a plurality of        individual light beams, at least one of the plurality of        individual light beams being diagonal relative to a conveyor        surface, an emitter, and a receiver;    -   The sensors may comprise sensors between sort modules to        determine when items pass from one sort module to another, each        such sensor being associated with the controller associated with        the sort module before or after the sensor, the controller        associated with the sensor being configured to report a jam        and/or stop the associated sort module when the associated        sensor does not sense an item when expected because of        communication received by the controller associated with the        sensor or when the associated sensor senses the item for longer        than a pre-determined amount of time;    -   The plurality of controllers of the modular package sorting        system is configured to determine, before moving each package        from one sort module to a next sort module, whether another        package is located on the next sort module and, if so, waiting        to move the package onto the next sort module until the other        package is no longer located on the next sort module;    -   A modular package sorting system including a plurality of        self-controlled sort modules configured to convey a package to a        one of a plurality of sortation points, and comprising a        plurality of controllers, each of the plurality of controllers        being associated with one sort module in the plurality of sort        modules, wherein each of the plurality of controllers is        configured to determine, when the package is received on the        corresponding sort module, whether to convey the package to a        subsequent sort module or to a sortation point associated with        the corresponding sort module, and, when the package is to be        conveyed to the subsequent sort module, is configured to        communicate with the controller associated with the subsequent        sort module by transmitting a request for a ready message to the        controller corresponding to the subsequent sort module and by        receiving the ready message from the controller corresponding to        the subsequent sort module, and to send the package to the        subsequent sort module after receipt of the ready message from        the controller corresponding to the subsequent sort module;    -   The message received from the controller associated with the        subsequent sort module indicates that the subsequent sort module        is ready to receive the package;    -   Each of the plurality of controllers of the modular package        sorting system is capable of controlling its respective sort        module independently of the sorter control computer;    -   Each of the plurality of controllers is configured to enable the        self-control of its respective sort module;    -   Each of the plurality of controllers has its own rule set;    -   Each of the plurality of controllers may comprise an identical        standard protocol for communicating with sort modules adjacent        to the associated one sort module;    -   The standard protocol is configured to enable the sending of the        package to the subsequent sort module;    -   Each of the plurality of controllers is autonomous from a        central operator supervisory control;    -   Each of the plurality of controllers is configured to receive        the electronic packet of data from an immediately preceding        controller in a sequence, and subsequently to convey the        electronic packet of data to an immediately succeeding        controller in the sequence;    -   Transmission of the electronic packet of data occurs at the same        time as the conveyance of the package from the associated one        sort module to the subsequent sort module or to the sortation        point associated with the one sort module;    -   The electronic packet of data further comprises information        identifying the package and/or the package's dimensions and/or        the package's weight;    -   Each of the plurality of controllers is further configured to        determine a speed among a plurality of speeds at which to send        the package to the subsequent sort module;    -   The speed determination depends at least on whether the package        is to be discharged to a sortation point associated with the        subsequent sort module;    -   The speed determination may depend at least on whether the        package is to be discharged to a sortation point associated with        a sort module downstream of the subsequent sort module;    -   The determined speed may differ from a speed at which the        associated one sort module received the package;    -   The plurality of speeds may be pre-installed on each of the        plurality of controllers;    -   The determining of the speed may depend at least on physical        dimensions of the package;    -   The plurality of sort modules of the modular package sorting        system comprises a series of sort modules physically connected        together end-to-end and being configured to convey items from a        first sort module to a last sort module over the series of sort        modules, and the controller associated with each sort module is        configured to communicate with controllers associated with sort        modules just before and just after in the series, when they        exist;    -   Each controller of the plurality of controllers is programmed to        carry out an identical operation, the operation comprising        receiving a sort point destination from an induction subsystem        or from a controller of an immediately preceding sort module,        using the sort point destination to determine whether to move        the package off to a side of the corresponding sort module to        the sortation point associated with the corresponding sort        module or to convey the package to an immediately subsequent        sort module, and, when conveying the package to the immediately        subsequent sort module, transmitting the sort point destination        to the controller associated with the immediately subsequent        sort module;    -   Each of the plurality of sort modules comprises a conveyor        surface configured to move items on the conveyor surface        forwards and to either side;    -   The conveyor surface may comprise a transport actuator        configured to move items on the conveyor surface forwards and        backwards, and a second transfer actuator configured to move        items on the conveyor surface to either side;    -   Each controller of the plurality of controllers is configured to        control mechanical operation of the conveyor surface of the        corresponding sort module, the plurality of sort point        destinations is located to one or more sides of the plurality of        sort modules and the plurality of sort modules are configured to        deliver packages to sort point destinations by conveying them to        the one or more sides of the sort modules;    -   Each controller of the plurality of controllers is programmed to        reduce speed of the conveyor surface of the corresponding sort        module when an item on the conveyor surface of the corresponding        sort module exceeds a dimensional and/or weight threshold;    -   Each controller of the plurality of controllers is programmed to        reduce speed of the conveyor surface of the corresponding sort        module when an item on the conveyor surface of the corresponding        sort module has a sort point destination located adjacent to an        immediately subsequent sort module;    -   Each controller of the plurality of controllers is programmed to        increase speed of the conveyor surface of the corresponding sort        module when an item on the conveyor surface of the corresponding        sort module has a sort point destination located beyond an        immediately subsequent sort module and a pre-determined number        of subsequent sort modules have no items on their respective        conveyor surfaces;    -   Each controller is configured to provide status information        about the corresponding sort module;    -   A modular package sorting system including sensors configured to        track movement of the package across the sort modules, wherein        the sensors comprise proximity sensors, through-beam sensors,        ultrasonic sensors, and/or reflective sensors;    -   The sensors comprise a plurality of angled through-beam array        sensors, and each of the plurality of angled through-beam array        sensors comprises a light beam array comprising a plurality of        individual light beams, at least one of the plurality of        individual light beams being diagonal relative to a conveyor        surface, an emitter, and a receiver;    -   The sensors may comprise sensors between sort modules to        determine when items pass from one sort module to another, each        such sensor being associated with the controller associated with        the sort module before or after the sensor, the controller        associated with the sensor being configured to report a jam        and/or stop the associated sort module when the associated        sensor does not sense an item when expected because of        communication received by the controller associated with the        sensor or when the associated sensor senses the item for longer        than a pre-determined amount of time;    -   The plurality of controllers is also configured to determine,        before moving each package from one sort module to a next sort        module, whether another package is located on the next sort        module and, if so, waiting to move the package onto the next        sort module until the other package is no longer located on the        next sort module;    -   A first controller in the plurality of controllers is associated        with a first sort module in the plurality of sort modules, a        second controller in the plurality of controllers is associated        with a second sort module in the plurality of sort modules, a        third controller in the plurality of controllers is associated        with a third sort module in the plurality of sort modules, the        first, second, and third sort modules being connected in series;    -   The second controller is configured to receive a query from the        first controller as to whether the second sort module is empty,        and to transmit a response to the query from the first        controller when the second sort module is empty, and when the        package received on the second sort module is to be transported        to the third sort module, selecting a speed from among a        plurality of speeds pre-installed in the second controller at        which to send the package to the third sort module, sending a        query to the third controller as to whether the third sort        module is empty, and only sending the package to the third        controller after having received a response from the third        controller to the query to the third controller;    -   Each of the plurality of controllers is further configured for        communication only with the controllers associated with sort        modules immediately preceding and immediately following the        associated one sort module, the communication including        responding to a request from the controller associated with the        immediately preceding sort module, receiving a packet of data        comprising the sort point destination for the package from the        immediately preceding sort module when the package is conveyed        from the immediately preceding sort module to the associated one        sort module, sending a request to the controller associated with        the immediately following sort module when the sort point        destination of the package is not the sortation point associated        with the one sort module, and sending the packet of data to the        immediately following sort module when conveying the package to        the immediately following sort module;    -   The modular package sorting system comprising a second plurality        of sort modules, each of the second plurality of sort modules        having only an immediately preceding sort module or an        immediately following sort module, but not both, such        immediately preceding sort module or immediately following sort        module being one of the plurality of sort modules; and    -   A modular package sorting system including a plurality of sort        modules configured to convey a package to one of a plurality of        sortation points corresponding to a sort point destination of        the package and comprising a plurality of controllers, each of        the plurality of controllers being associated with one sort        module in the plurality of sort modules, wherein each of the        plurality of controllers is configured to communicate with one        or more other controllers in the plurality of controllers and to        determine whether to convey the package from the associated one        sort module to a subsequent sort module or to a sortation point        associated with the one sort module, based on the sort point        destination for the package.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated herein and form a partof the specification, illustrate exemplary embodiments and, togetherwith the description, further serve to enable a person skilled in thepertinent art to make and use these embodiments and others that will beapparent to those skilled in the art. The invention will be moreparticularly described in conjunction with the following drawingswherein:

FIG. 1 is a diagram illustrating a top-level control architecture,according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating an induction system, according to anembodiment of the present invention.

FIG. 3 is a diagram illustrating an induction system hand-off to thesorter sub-system, according to an embodiment of the present invention.

FIG. 4 is a diagram illustrating a module to module hand-off in thesorter sub-system, according to an embodiment of the present invention.

FIG. 5 is a diagram illustrating sort module components, according to anembodiment of the present invention.

FIG. 6 is a diagram illustrating a sample module design, according to anembodiment of the present invention.

FIG. 7 is a diagram illustrating an angled thru-beam sensor array,according to an embodiment of the present invention.

FIG. 8 is a diagram illustrating an adaptive speed control for a largepackage, according to an embodiment of the present invention.

FIG. 9 is a diagram illustrating an adaptive speed control foranticipated sortation, according to an embodiment of the presentinvention.

FIG. 10 is a diagram illustrating a jam detection logic, according to anembodiment of the present invention.

FIG. 11 is a diagram illustrating continuous sortation, according to anembodiment of the present invention.

FIG. 12 is a diagram illustrating zone purging, according to anembodiment of the present invention.

DETAILED DESCRIPTION

This specification discloses one or more embodiments that incorporatefeatures of the invention. The embodiment(s) described, and referencesin the specification to “one embodiment”, “an embodiment”, “an exampleembodiment”, etc., indicate that the embodiment(s) described may includea particular feature, structure, or characteristic. Such phrases are notnecessarily referring to the same embodiment. When a particular feature,structure, or characteristic is described in connection with anembodiment, persons skilled in the art may affect such feature,structure, or characteristic in connection with other embodimentswhether or not explicitly described.

In the several figures, like reference numerals may be used for likeelements having like functions even in different drawings. Theembodiments described, and their detailed construction and elements, aremerely provided to assist in a comprehensive understanding of theinvention. Thus, it is apparent that the present invention can becarried out in a variety of ways, and does not require any of thespecific features described herein. Also, well-known functions orconstructions are not described in detail since they would obscure theinvention with unnecessary detail. Any signal arrows in thedrawings/figures should be considered only as exemplary, and notlimiting, unless otherwise specifically noted.

The description is not to be taken in a limiting sense, but is mademerely for the purpose of illustrating the general principles of theinvention.

It will be understood that, although the terms first, second, etc. maybe used herein to describe various elements, these elements should notbe limited by these terms. These terms are only used to distinguish oneelement from another. For example, a first element could be termed asecond element, and, similarly, a second element could be termed a firstelement, without departing from the scope of example embodiments. Asused herein, the term “and/or” includes any and all combinations of oneor more of the associated listed items. As used herein, the singularforms “a”, “an” and “the” are intended to include the plural forms aswell, unless the context clearly indicates otherwise.

It should also be noted that in some alternative implementations, thefunctions/acts noted may occur out of the order noted in the figures.For example, two figures shown in succession may in fact be executedsubstantially concurrently or may sometimes be executed in the reverseorder, depending upon the functionality/acts involved.

FIG. 1 provides an overview of the top-level control architecture of thesorter design to illustrate the distributed control architecture betweenthe induction sub-system and the sorter sub-system.

The induction sub-system (1) is where a package (2) enters the sorter.The sorter control computer (3) controls the conveyor sections (4) ofthe induction sub-system to move the package in the direction of flow(5). The sorter control computer collects information about the package,determines its sort point destination, and creates a data set specificto each package. The data set is sent over the sort module I/O network(6) and delivered to the first PLC (7) that is resident in the firstsort module (8) of the sorter sub-system (9). Each subsequent sortmodule in the sorter sub-system is identical to the first sort moduleand has its own PLC to move the package in the direction of flow (10) orto move the package in the direction of sortation (11) to waiting sortcontainer (12) or conveyors. The data set and the package aretransferred sequentially through each sort module PLC in the directionof the sorter (13) until the package is sorted and the sortation iscomplete for that package. The sorter sub-system (9) can be extendedwith additional sort modules without impacting the induction sub-system(1) or the sorter control computer (3).

FIG. 2 describes the details of the induction sub-system (1) where thesorter control computer (3) provides supervisory control for the sortersystem and interfaces with the different hardware systems to scan, weighand dimension the package. The sorter control computer (3) controls theindividual conveyor sections (4) to transport the package (2) throughthe induction sub-system. The sorter control computer (3) collectsinformation about the package as it moves through a camera (14),dimensioner (15), and weighing system (16). The sorter control computeruses this data to create a record specific for each package and todetermine how the package should be sorted in the sorter sub-system (9).The sort point destination can be determined locally by the sortercontrol computer (3) or it can be determined by remote server (17)accessed by a data connection (18). Sort point destination is typicallydetermined based primarily on destination address, particularlydestination zip code, but may also be determined based for example onpackage size and/or weight and/or other data. The logic used to turndata about the package into a sort point destination may be viewable andchangeable from the sorter control computer. There may be multiplelevels of such sorting logic, e.g. primary, secondary, and tertiary. Forexample, one level may narrow sort points possibilities based on onefactor such as address, another may narrow further based on additionalcriteria such as size. Mail handlers, for example, have size limitationsand weight restrictions for mail bags, so hand-carry routes may excludepackages above a certain size and/or weight which may have to go by caror truck, and hand-carry versus car/truck delivery may be assignedseparate sort points. Once the sort point destination has beendetermined, data that includes the sort point destination is preparedfor the package and it is sent to the first sort module PLC (7) usingthe sort module I/O network (6), which may be hard-wired such as withEthernet cable, or based on Wi-Fi or other wireless communication.

The induction sub-system provides the overall control of the sorteroperations and controls the package induction function. The sequentialprocess for package induction provides an automatic check against“no-read” or bad barcodes. If a barcode (or other machine readable code,depending on the implementation) is successfully read but indicates thatthe package (or other object) should not be in the system, it may besorted through into a reject bin. If the package (2) is not read by thecamera (14), the sorter control computer (3) will not move the packageto the next conveyor section and the induction sequence will stop. Thisgreatly reduces the number of “no-reads” and reduces the number of timesa package has to be re-run. The process may resume once the package'sdestination address is manually input or successfully manuallyre-scanned, or start on another package once the package is removed fromthe induction sub-system. An operator may manually enter the relevantinformation (e.g. destination address) or re-scan (e.g. by waving thebar code in front of the bar code scanner) to ensure the necessaryinformation is received, at which time the sorter control computer willmove the package to the next conveyor section. In some embodiments if anoperator is not available a package may be diverted to a reject area forre-scanning at a later time while induction of other packages continues.A system where induction halts until necessary information is receivedprovides an advantage over existing systems, in which barcode readinghappens well downstream and there is no way to reposition or manuallymanipulate the packages, so typically about 10% of packages are notread, and go to a reject bin to be re-run.

Damaged barcodes are common in the shipping industry, so the sortercontrol computer also supports the manual input of routes or sort pointdestination bins to facilitate operations. In a mail handlingapplication, typically each sort point corresponds to a different mailroute, each route being assigned to a separate delivery vehicle. Forsuch manual input cases, the sorter computer allows the operator to usea keyboard (19) or touch screen monitor (20) to manually input the routeor sort point destination bin, and the induction sub-system will processthe package according to the operator's input.

The sorter control computer provides another very useful feature: itallows the operator to back up and remove a package in the inductionsub-system and clear the data already collected. This feature is used ifthe package becomes jammed somewhere in the induction conveyor sectionsmidway through the data collection process. The sorter control computerprovides a “back up” pushbutton (21) for the operator for quickresolution if an error is detected part-way through the inductionsub-system (1). Pressing the pushbutton will notify the sorter controlcomputer (3) to stop the motion of the conveyor sections (4) and holdingthe button down slowly reverses them until the package is within reachof the operator so that it can be repositioned or removed. Aftermanually acquiring the jammed package, an operator rescans its barcodeto re-induct the same package or scans a different package into thesystem and resumes operations. The sorter control computer automaticallyreplaces the data associated with the jammed package with the newpackage data.

The sorter control computer (3) can also keep track of the volume ofpackages sorted to each sort point based on the sum of the volumesdetermined by the dimensions of packages with the same sort pointdestination. This data can be used to provide the operator notificationwhen a particular bin is likely to be getting full and needs to bechanged out. The threshold for providing such a notification may beuser-configurable, via e.g. the sorter control computer, and may forexample be when the estimated volume of packages delivered to a sortpoint is within 20% of the capacity at that sort point. The estimatedvolume of packages may vary depending on size and angularity of packages(or other objects) which may result in a looser or denser pack. In someembodiments, a user can select approximate size and shape ranges of theitems to be scanned and a density factor may be estimated, from which anappropriate volume and fill safety threshold can be assigned. Operatorscan also adjust the threshold on the fly after seeing whether containersare too full or too empty when a change-out is indicated.

Sort point bin volume may be set up in the sorter control computer whenfirst setting up the system, and updated manually as necessary using themanual input (or remotely) when bins are changed. Alternatively, binsmay have a barcode, RFID chip or similar storing volume information anda corresponding sensor may read the volume information and provide it tothe sorter control computer. In some embodiments, a set of containerswith known volumes are provided for use with the system as sort pointbins and these volumes may come pre-loaded in the sorter controlcomputer. Packages with known volumes, e.g. flat rate shipping boxes,may also have their volume pre-loaded in the sorter control computer. Inother embodiments, a user may supply containers and the sorter controlcomputer may communicate with them to automatically identify theirpertinent characteristics. Keeping the bins from overfilling withpackages is an important operational feature, since an overfilled bincan cause packages to back up and then cause a jam in the sortersub-system that is more difficult and time-consuming to resolve.

When jams are detected by any of the sort modules (22), the jam isreported to the sorter control computer. The sorter control computerwill log these errors for analysis and can notify maintenance personnelof the error rates and the location of the errors in the sorter. Thesorter control computer can initiate remedial actions to slow down thetransport speed of troubled sort modules or skip the module altogetheruntil the source of the error can be determined and a more permanentrepair can be made, for example if the frequency of jams on a given sortmodule exceeds a preset threshold over a certain period of time. When asort module is “skipped”, all packages are simply conveyed by that sortmodule to the next sort module—none are discharged off the sides.Packages that should have been discharged by that sort module may beconveyed ultimately to a reject bin from which they can be collected andre-entered into the sorting stream once the sort module is put back intofull operation.

FIG. 3 describes the induction sub-system hand-off to the sortersub-system (9). The details of the induction sub-system are as describedabove herein, and particularly as described in FIG. 2. Specifically, thesorter control computer (3) controls the individual conveyor sections(4) to transport the package (2) through the induction sub-system. Thesorter control computer (3) collects information about the package as itmoves through a camera (14), dimensioner (15), and weighing system (16).The sorter control computer uses this data to create a record specificfor each package and to determine how the package should be sorted inthe sorter sub-system (9). The sort point destination can be determinedlocally by the sorter control computer (3) or it can be determined byremote server (17) accessed by a data connection (18). Additionally, thesorter control computer also supports the manual input of routes or sortpoint destination bins to facilitate operations. In a mail handlingapplication, typically each sort point corresponds to a different mailroute, each route being assigned to a separate delivery vehicle. Forsuch manual input cases, the sorter computer allows the operator to usea keyboard (19) or touch screen monitor (20) to manually input the routeor sort point destination bin, and the induction sub-system will processthe package according to the operator's input. The sorter controlcomputer also allows the operator to back up and remove a package in theinduction sub-system and clear the data already collected. This featureis used if the package becomes jammed somewhere in the inductionconveyor sections midway through the data collection process. The sortercontrol computer provides a “back up” pushbutton (21) for the operatorfor quick resolution if an error is detected part-way through theinduction sub-system (1). When jams are detected by any of the sortmodules (22), the jam is reported to the sorter control computer. Thesorter control computer will log these errors for analysis and cannotify maintenance personnel of the error rates and the location of theerrors in the sorter. The sorter control computer can initiate remedialactions to slow down the transport speed of troubled sort modules orskip the module altogether until the source of the error can bedetermined and a more permanent repair can be made.

During the hand-off from the induction sub-system to the sortersub-system (9), initially, the first sort module PLC (7) willcommunicate with the sort computer (3) in the induction sub-system (1)to move the package (23) onto the first sort module (8). To make thistransition, the sorter control system computer (3) will communicate withthe first sort module PLC (7) using the sort module I/O network (6) andrequest a “ready” message. If the first sort module (8) is clear, thePLC (7) will respond back with a clear-to-send message and the controlsystem computer (3) will activate the conveyor to move the package ontothe first sort module (8). At the same time, the sorter control computer(3) will transmit the package data set to the first module PLC (7) ofthe first sort module using the sort module I/O network (6). The dataset will identify key information about the package including thepackage identification, the package length, and the package finaldestination. Additional data may include, the width, height, weight orany other relevant information.

FIG. 4 shows the module-to-module hand-off within the sorter sub-system.The details of the induction sub-system are as described above herein,and particularly as described in FIG. 2. Further, the details of theinduction sub-system hand-off to the sorter-subsystem are as describedabove herein, and particularly as described in FIG. 3. As describedbelow, the transitions between sort modules are performed with the samelogic, and the basic transaction is the same between all sort modules.Each sort module has local and independent control to accept a packagefrom an upstream module, transport the package in the direction oftravel (24), discharge the package to the right or left sort direction(25), or coordinate with the next module to accept the package. When apackage (26) is waiting on the first sort module (8) ready to move tosecond sort module (27), the first sort module PLC (7) software sends aready-to-send signal from the second sort module PLC (28). If no packageis present on the second sort module (27), the second sort module PLC(28) will send a clear-to-send message to the first sort module PLC (7)and the package will move to the second sort module (27). The datapacket specific to the package will be sent from the first sort moduleto the second sort module PLC when it is cleared to send the package.

If a package is present on the second sort module (27) or it isotherwise unavailable, the package (26) will wait on the first sortmodule (8) until such time that the second sort module (27) is clear anda clear-to-send message is sent to the first sort module PLC.

FIG. 5 illustrates the sort module components. Each sort module (22) iscomprised of a conveying surface (29) that is equipped with a transportactuator (30) that will move the package over the transfer in thedirection of travel (31). A second transfer actuator (32) will divertthe package off the conveyor at a predefined position to “sort” thepackage into an adjacent conveyor or container. Each sort module iscontrolled locally by the sort module PLC (7) which is connected toadjacent sort modules through the sort module I/O network (6). A packagesensor (33) is used to detect the leading and trailing edges of packagesthat are arriving at the sort module, which can be used to determinewhen a package has arrived on the sort module. Leading and trailingedges can also be used to determine or verify size and/or orientation ofpackages, although this information may be obtained during induction, aspackages may shift during transport and become effectively longer orshorter in the longitudinal direction of the conveyor surface. Passingof the leading and trailing edges may also be used to determine speed ofthe package, although this is typically known from motor encoders of thesort module. An indicator lamp (34) is provided to indicate conditionsat the sort modules and a push button (35) is provided for operatorinputs (e.g. to stop the sort module or to put it back in operationafter a jam has been cleared).

The sort module PLC (7) has a unique identifier number that correspondswith the sort module position in the overall sorter string. The sortercontrol computer can store these identifier numbers in connection withpositions in the sorter string. In some embodiments, the sorter controlcomputer may have a layout of the sorter, which may be pre-loaded oroperator-entered, and then pre-assigned module identifiers may beentered in connection with each position of the layout. In otherembodiments, the layout comes with pre-generated numbers for eachposition in the layout, and an operator then assigns each number to thecorresponding sort module based on its position in the sorter string viathe PLCs. In another embodiment, the sorter control computer canauto-configure the position-identifier relationship without operatorinvolvement. The sort modules may be set up, a configure button (e.g.hard or soft button) pressed by the operator, and the sorter controlcomputer may determine location of each sort module (for example usingthe network connecting them) and automatically assign the appropriateidentifier.

Each PLC has the same set of control program(s) to interface with thepackage sensor (33), the transport actuator (30) and the transferactuator (32). The transport actuator moves the package across the sortmodule (22) to the next module. This actuator can be a powered conveyorbelt, mechanical powered pusher, or other means to transport thepackage. This actuator is activated when the PLC receives permissionfrom the next sort module's PLC, indicating that the next sort module isfree to receive the package. Thus, in such embodiments each sort modulewill have no more than one package at any given time (excluding jamconditions). Since a PLC, in normal operation, will not give thego-ahead to the previous sort module until its conveyor surface isclear, no more than half of the sort modules will have a package at anygiven time, and no more than half of the sort module conveyor surfaceswill be operating at any given time. When operating at less than fullcapacity, the utilization rate is substantially lower than 50%. Becauseof this, sound levels are substantially lower than for conventionalsorting systems with a single long conveyor belt that is essentiallyalways operational. For example, even at full capacity total soundenergy can be reduced by 50%. No hearing protection is needed, which isa significant improvement over conventional systems. An exception tothis stop/start method of operation would be purge/train mode, in whichthe sort modules in that operating mode do not wait for permission andsimply all activate their conveyor surfaces together in order to conveyall packages off the end of the line and discharge them, for example toclear jams. The packages discharged off the end of the line can then bere-inserted into the induction sub-system if needed. Another exceptionwould occur when packages are allowed to accumulate and stop, one permodule, behind a downstream jam, analogous to a roadway traffic jam.Once the downstream jam is cleared, the sort modules activate to movethe backed-up packages forward one at a time, restoring the normalspacing.

The transfer actuator (32) will propel the package off of the sortmodule (22) to the right or left to sort the package into a container,chute, or other type of discharges. Similarly, this actuator can be aconveyor belt, mechanical powered pusher or other means to propel thepackage to the right or left.

The sort module PLC (7) also handles local communications with theindicator lamps (34) and pushbuttons (35) as well as networkcommunication with the upstream PLC (36) and downstream PLC (37), andsorter control computer (3). The PLCs can communicate with the sortercontrol computer and with the adjacent PLCs. In some embodiments, allPLCs and the sorter control computer are listening on a shared bus, soany communication can be sent to any device on the bus if properlyaddressed. Two sets of indicator lamps and pushbuttons may be providedfor convenience so that one set may be located on either side of thesort module.

The data set for each package is generated by the sorter controlcomputer and communicated to the sort module PLC (7) from the upstreamPLC (36) as the package physically arrives at the sort module. The logicprogrammed in the sort module PLC (7) will give the upstream modulepermission to send the package, determine what speed to run the conveyorbelt and whether the package should be diverted to the right, to theleft, or passed along to the next module. If the package sort pointdestination is further downstream of the sorter, the sort module PLC (7)will communicate the data set to the downstream PLC (37) and requestpermission to send the package to the next sort module.

In this embodiment, package data is sent along with the package from PLCto PLC and includes package identification, address data, size, sortpoint destination per the sort scheme in effect, etc. Speed for thepackage is determined according to pre-programmed rules. For example, asort module may run at regular speed unless the package is above athreshold size and/or being sorted on that module or the next, in whichcase speed may be reduced for example to ¾ of regular speed. If forexample traffic is low and/or a package is not to be sorted until fardown the line, speed may also be increased from regular speed in someembodiments.

The sort module PLC (7) will also turn on or off the indicator lamps(34) based on supervisory commands from the sorter control computer (3).As non-limiting examples, the indicator lamps can be used to show thatthe sorter is on, a flashing lamp can show that there is a jam detectedin the sort module, or a slow flashing lamp can be used to show that thesort point destination bin should be getting full, based on aggregateddimensional data, and may require operator attention.

In a similar fashion, the sort module PLC (7) can interface with thepushbutton (35) to communicate operator inputs to the supervisory sortercontrol computer, which is not shown in FIG. 5 but can be, for instance,the sorter control computer (3) as shown in any of FIGS. 1-4. As anexample, an operator could stop the sorter from discharging to aspecific position while the discharge container is being changed out, orwhile a jam is being cleared or maintenance function being performed.The module may be completely stopped, or may be allowed to run and passpackages on to the next sort module, but not discharge packages to thesort point where the discharge container is being changed. Any modulemay be turned on or off at any time. This provides a very importantadvantage over existing sortation systems, in which a single conveyorconveys all packages and the entire system must be shut down to preventpackages from being discharged while a container is being changed,maintenance performed or jams cleared. In contrast, embodiments of thepresent invention allow for such operations to be carried out whilekeeping the system almost completely operational. Pressing thepushbutton (35) would be an input to the sort module PLC (7) and wouldbe communicated through the sort module I/O network (6) to thesupervisory control computer (3).

FIG. 6 illustrates one sample module design (cf. U.S. patent applicationSer. No. 15/916,248, filed Mar. 3, 2018). This is one of many mechanicalsolutions that uses two actuators to transport and sort packages. Inthis design, two conveyor belts are mounted crosswise to each other andthe top conveyor incorporates a multitude of rotating elements thatcarry the package on top and the rotating elements are supported by acrosswise conveyor belt underneath. The coordinated movement of the twoconveyor belts will cause the package to move in a straight line orchange directions to the right or left for discharge. The transfermodule frame (38) provides the structure to support the top plasticconveyor belt (39) that has internal rotating elements (40) and ismounted above flat transfer belt (41). The frame supports the conveyordrive roller (42) for the top plastic belt and the drive roller (43) forthe transfer belt mounted underneath. The rotating elements of the topplastic conveyor rotate when the conveyor is in motion because of theircontact with the flat transfer belt mounted underneath and a package onthe top surface will be propelled in the direction of the belt motion.Additionally, when the transfer belt (41) underneath is activated by itsdrive roller (43), the rotating elements (40) of the top belt willchange direction and a package sitting on top of the conveyor will bepropelled to the right or left for sortation. This is a particularlyefficient mechanical solution and the subject of the patent applicationnoted above. However, many other mechanical solutions are possible andanticipated.

FIG. 7 illustrates how an angled through-beam array is used to detecteven the smallest package as it moves between sort modules. The controlsystem for this modular sorter design requires the accurate tracking ofpackages as they move from sort module to sort module. This is achallenging requirement for a sorter that must handle a wide range ofpackage sizes and package types. Typically, this tracking is performedwith simple sensors such as proximity sensors, through-beam sensors,ultrasonic sensors, or reflective sensors. However, each of these sensortypes is limited to what types and sizes of packages can be detected.

The angled through-beam array shown in FIG. 7 is a series of individualthrough-beam sensors mounted in a common enclosure. Each through-beamarray has an emitter (44) and receiver (45). The light beam array (46)is a screen of individual light beams that are spaced very closetogether—here a dozen beams spaced ¼″ apart. The emitter and receiversare also mounted at an angle (47) to cover the area between the sensorswith a diagonal pattern of light beams. The diagonal pattern of lightbeams greatly improves the performance of this system to detect verythin packages (48) moving between the conveying surfaces (49). Packagesthat are thinner than the spacing between light beams will block one ormore angled beams (50) and the package will be detected. This featuregreatly extends the sorter's versatility to handle a wide variety ofpackage sizes from large boxes to flat envelopes to even single businesscards. If it is known that objects of a certain thinness will not beencountered by the system, cheaper sensors having fewer, more widelyspaced, beams may be used. For example, for shoebox-size items, a simplesingle through-beam would typically be sufficient. The sensors arepositioned in between sort modules to detect when a package (or otherobject) transitions between one sort module and the next.

FIG. 8 illustrates one of the adaptive speed control logic features ofthe sort module PLC programming when handling larger package sizes. Thesorter must accurately position each package before it is dischargedfrom the sort module. The proper position and timing will changedepending on the size of the package being processed. The larger apackage is relative to the sort module, the more precise the positioncontrol must be to ensure the package is properly delivered to the sortpoint destination and not for example onto the floor. Position of thepackage may be determined based on the sensor shown in FIG. 7 whichdetects the package's entry onto the sort module, combined with timepassed since the package's entry was detected (leading or trailingedge), using the leading or trailing edge of the package, and/or thespeed of the conveying surface. In some embodiments a single sort modulemay feed multiple sort points/containers on a single side, in which caseposition of a package on the conveyor surface is important, however manyimplementations have only a single sort point to either side of a givensort module. The sorter is designed to run as fast as possible tomaximize its throughput. However, larger packages have less availableroom to be diverted or stop on a given module size. In normal operation,stopping is required when the downstream module is not clear, i.e. itcontains a package. Attempts to divert or stop a large package in aninsufficient distance and timeframe may result in the package slippingon the conveying surface and overrunning its sort module, missing itssort point destination, or leaving the sort system entirely. Toaccommodate these packages, the PLC is programmed to adapt to the largerpackage and automatically slow down the conveyor speed when a largerpackage is encountered.

What constitutes a larger package and how much the speed needs to bereduced may be pre-programmed, or operational adjustments can bedetermined empirically. The measure of size may be captured in theinduction sub-system by an imaging-type dimensioner or by calculatingpackage length as the package crosses a through-beam sensor array in theinduction sub-section running at a known rate of speed from leading edgeto trailing edge. Calculations of appropriate speed reduction can becomplex, as they are affected by many factors, including package mass,coefficient of friction of packaging material and its irregularities onconveyor material and contact points, differenced between longitudinaland lateral movement, motion of a particular package when hit withdiverting forces, etc. Although such calculations are known and may beperformed, to higher or lower accuracy based on the information andcalculating resources available, they are largely unnecessary. Instead,the system may be programmed to reduce speed to a predeterminedthreshold of normal operating speed, for example ¾, when package lengthto module length is greater than a threshold ratio. Multiple thresholdsfor length ratio and corresponding speed reduction may be programmed—forexample ¾ speed at a ½ length ratio, ½ speed at a ¾ length ratio, etc.The system may then log jam/reliability rates and determine whether thespeed reduction at a given length ratio is adequate (for example using aprogrammed reliability threshold, e.g. 95% accurate non-jam sorting) andadjust if indicated, or based on operator input. The appropriate speedat given package length ratios to achieve a desired reliability for agiven implementation may be determined empirically by the sorter controlcomputer as speeds, length ratios, and jam frequency/reliability arelogged. Operating speed as a function of length ratio may beautomatically adjusted when reliability is detected to vary from adesired level.

As previously described herein, package dimension data is collectedduring the package induction process and is communicated by the sortmodule I/O network (6) to the individual sort module PLC with the datapacket that travels from sort module to sort module with the physicalpackage. If a large package (51) exceeds a preprogrammed value, the sortmodule PLC (52) on the sort module (53) may decrease the transportvelocity (54). The transport velocity (54) is automatically reset to thedefault speed after the package has left the sort module. As the packagemoves to the next sort module (55), the next PLC (56) program maysimilarly decrease the transport velocity (57) in that sort module forthat package and automatically reset to the default value when thepackage has left that sort module.

For example, each sort module starts when the sensor located in the gapimmediately before the sort module detects the leading edge of apackage. Packages will pass over a sort module without stopping if thenext sort module is clear and ready to accept the next package. The sortmodule will continue to run and transport the package to the downstreamsort module and stop when the sensor at the beginning of downstream sortmodule sees the trailing edge of the package.

However, if the next module is not clear, the package will have to stopbefore entering the next module. In this case the first sort module willstart as before when the entrance sensor detects the leading edge of apackage. However, the sort module must stop the package before blockingthe entrance sensor of the downstream zone. To stop the package in time,the same sensor that detects the leading edge of the package is alsoused to detect the trailing edge of the package and signal the zone tostop.

If the sort module is 40 inches long, and transporting a 10 inch packageat 40 inches per second, the package will have 30 inches, or ¾ secondsafter the trailing edge of the package clears the entrance sensor to thezone and before the leading edge is detected by the entrance sensor tothe next sort module. However, if the same sort module is transporting alarger 20 inch package, this package will only have 20 inches, or ½second after the trailing edge clears the entrance sensor.

In some cases, this may not be enough time or distance for the packageto stop, if it is required to be stopped, before triggering the entrancesensor of the next sort module, causing a jam condition.

The adaptive features of the program running on the PLCs of the sortmodules may be used to slow the transport speed of the sort module toincrease the package stopping time to avoid a jam condition. In thisexample, the PLC of the sort module knows that the package is 20 incheslong (as determined at induction of the package and/or by the sensor).Based on pre-programmed values, or machine learning, the PLC knows 40in/s is too fast for the package to be stopped, if it required to stopif a package that is occupying the next downstream module. The PLCtherefore slows the transport speed of the module to 20 inches persecond, giving the 20 inch package 20 inches or a full 1 second to cometo a stop, if it is required to stop, before causing a jam. Theseadaptive features allow the sorter to run at maximum throughput ratesand dynamically adjust the transport speed to improve reliability over awide range of package sizes.

FIG. 9 illustrates another important use of the adaptive speed control:slowing down the conveyor speed in anticipation of an upcoming sortpoint destination. The wide variety of package types presents varyingmechanical interactions with the conveying surface. Purely as anon-limiting example, some packages can be slippery and take longer tochange directions and discharge from the sorter to avoid slipping on theconveyor surface. Overshooting a sort point can cause a jam conditionand require operator intervention.

Dynamically slowing the transport conveyor based on the knowledge thatthe package will be sorted in the next sort module greatly increases thereliability for package sortation by increasing the timing tolerance toinitiate a discharge. The ability to anticipate and automatically adjustthe speed of the conveyor modules, while the packages are beingtransported, greatly increases the accuracy and reliability of both thetransport and the sortation functions and avoids unnecessary jams frompackages failing to stop or failing to discharge in the available timeand length of the sort module. The decision to slow down the transportconveyor can also be programmed as a function of the package. Smallpackages may not require any speed adjustment to allow a downstreampackage to be diverted. However, larger packages have less tolerance andwill frequently require a speed adjustment to maintain maximumreliability.

FIG. 9 illustrates the control logic where a package (58) in sort module(59) is going to be sorted (60) in the next sort module (61). The PLC(62) may reduce the transport velocity (63) so that the package willenter the next module (61) with less speed and hence less chance ofsliding and overshooting as it turns and is sorted (60).

Each sort module PLC has this same adaptive feature in its controlprogram to slow down the transport speed of a package on its module,assuming the package is destined to be sorted in the next downstreamsort module. This logic will follow each package as it moves down thesorter based on the data set prepared by the sort computer, which is notshown in FIG. 9 but can be, for instance, the sorter control computer(3) as shown in any of FIGS. 1-4, and relayed to the sort modulesthrough the sort module I/O network (6). No further control is requiredfrom the sort computer.

Similarly, the sort module PLC programs can look ahead and increase thepackage transport speed based on the knowledge that the next few zonesare clear of traffic and there is no impending transfer/sort event.

Collectively, the adaptive speed modification programs that runindependently in each of the sort modules can improve the overall sorterthroughput and reliability without burdening the sorter control computerwith calculating the local conditions at each sort module.

Jam detection is an important feature of the sorter. Stopping the sorterwhen a jam is detected avoids mis-sorts and provides timely alerts foroperators to clear the jam and resume full operational throughput. Whena jam is detected, it is reported to the sorter control computer andonly the sort module(s) associated with the jam stops processing and itsindicator lamp is turned on to notify operators. Jams may be detectedbased on a through-beam sensor sensing a package when none wasexpected—i.e. the sort module before the sensor was not given thego-ahead to proceed, which may indicate a package slid into the sensorarea when it should have stopped or been diverted off the sorter- or notsensing a package when one was expected—i.e. the sort module before thesensor was given the go ahead to convey the package onward, which mayindicate that the package is stuck on something or fell off the conveyorsurface. Until the jam is cleared the sort module(s) associated with thejam will not send a ready signal to the preceding sort module, soadditional packages will not be conveyed onto it.

FIG. 10 illustrates the jam detection logic that runs on each of thesort module PLCs independent of the sorter control computer in theinduction sub-system. In this illustration, the package (63) has justcleared the sensor (64) as it arrives on the sort module (65). However,the next downstream package sensor (66) has just detected a package (67)moving to sort module (61) much sooner than anticipated, based on thelength of the expected package (63) and sort module transport velocity(68).

The unexpected early arrival is communicated to the sorter controlcomputer, which is not shown in FIG. 10 but can be, for instance, thesorter control computer (3) as shown in any of FIGS. 1-4, as an “unknownpackage” and the package transport actuator (30) is stopped in the sortmodule that is affected. The sort module PLC (69), which is connected tothe sorter control computer through the sort module I/O network (6),will flash the indicator lamp (34) and the operators are instructed tosimply remove the packages in that area and re-start the sorter bypressing the pushbutton (35).

Several different jam detection routines are running in each sort modulePLC based on the anticipation of detecting the arrival of packages at aspecific module. Here are some non-limiting examples of such routines:

A package did not arrive when expected. Similar to the “unknown package”jam described above, this jam is based on not seeing the package whenanticipated. If a package is not detected by the package sensor when itwas anticipated, the PLC will report a package transport jam, and thesorter control system will stop the conveyor module, raise an alarm, andindicate that the package failed to transport.

Package or debris jammed on conveyor. If a package detecting sensor,such as a through-beam sensor as described herein, is blocked andremains blocked between sort modules, the module PLC will report atransport jam. The control system will likewise stop the conveyormodule, raise an alarm, and indicate that the packages(s) are jammed onthe conveyor.

In all cases, the sorter control system will provide notification to theoperator of where the jam(s) is detected. This notification is availableon the sorter control screen and also with indicator lamps located ateach sort module. When a jam is reported, the sorter control system willstop the sort modules where the jam is detected and flash the lamps toshow the operator where the problem is detected. An additionalnotification will be shown on the control system display. Operators willclear the jam(s) in the affected areas and remove the packages. Theoperator will notify the control system that the packages have beenremoved and the jam resolved by pressing a pushbutton co-located withthe indicator lamp. Depending on how the sorter is staffed withoperators, a secondary push button located at the operator's station maybe used to clear all jam conditions from the same point. Once the jamhas been cleared, the affected sort modules resume operations.

It is important to note that the independent PLC control of the sortmodules will allow the portions of the sorter outside of the area wherethe jam is detected to continue to process packages until the packageflow is backed up by the stopped modules. This is an important featuresince jams are frequently resolved before the sorter is stopped from abackup of stopped packages.

The sorter control system keeps track of the number of jams and the typeof jam for each sorter module. A diagnostics log is kept to identifyproblematic sorter sections where additional maintenance oversight iswarranted. Diagnostic logging can also be used by the sorter controlsystem to provide inputs for the dynamic speed control of the sortmodules to automatically compensate for underperforming sort modules,where mechanical wear or contamination has changed the performance ofthe transport and transfer mechanisms.

FIG. 11 illustrates the sorter's capability for continuous sorting inareas that are not affected by a local jam. This is an importantability, since maximum throughput is always a key consideration forsorter systems. The modular architecture allows the sorter to continueto sort packages to discharge bins that are unaffected by a localizedjam or bin full condition. This feature allows the sorter to continuedoing productive work for a period of time until the jam or bin fullcondition is cleared. Frequently these conditions can be cleared beforethe package flow backs up and blocks the induction of new packages. Inthese cases, the jams or bin change-outs will not impact the overallsorter throughput.

FIG. 11 shows that sort module (69) has detected a jam and the modulehas stopped. The sort module PLC in module (70) has not gotten a “clearto send” signal so the package (71) is stopped in module (72) and iswaiting for module (69) to be cleared. Package (73) is destined furtherdown the sorter but must wait until module (72) is clear. However,module (74) and module (75) can continue to transport and sort packageswithout interruption.

FIG. 12 describes how the sorter control computer can also override thelocal sort module PLC(s) to turn on the transport actuators of multiplesort modules to all run together to move all packages at once, withoutthe intra-module communication and control. This function can be used topurge the sorter of packages or clear multiple jam conditions when it iseasier to purge a zone of modules and re-run the packages on the sorter.This purge function can also be run in just a zone where only a selectgroup of modules are run as a group to the end of the sorter. Packagesupstream and downstream of the reject zone would sort as usual and whenthe affected sections are run off the end, the entire sorter operationwill be back to normal.

FIG. 12 illustrates this purge function where a set of modules has beenidentified as the purge zone (76), which includes, among other sortmodule PLCs, the sort module PLC in module (70). These sort modules willoperate together as one large zone to transport all of the packagestogether by running the entire zone as one. The local PLC logic in themodules is overridden by the sorter computer to move the group ofpackages as a whole to the end of the sorter and into the reject bin(77). The sort modules in the purge zone (76) keep transporting packagesforward but do not attempt to sort them off to the side, to avoidsorting errors. Other packages on sort modules outside of the purge zonewill operate as normal, passing packages from module to module andsorting accordingly. Package (78) in the illustration will move to thenext module when package (79) has been sorted off of the module. Package(80) will divert and sort as normal. Purge zone (76) follows the jammedpackages down the line of sort modules. When the jammed packages reachsort module (74), purge zone (76) will include sort module (74) and theprevious sort module, but not the sort module previous to that, and soon until the jammed packages are in the reject bin, at which time nosort modules will be in the purge zone (76) (unless a new jam conditionand new purge zone has been established in the meantime).

While specific preferred embodiments and examples of fabrication andtesting of the invention have been illustrated and described, it will beclear that the invention is not so limited. Numerous modifications oralterations, changes, variations, substitutions and equivalents willoccur to those skilled in the art without deviating from the spirit andscope of the invention, and are deemed part and parcel of the inventiondisclosed herein.

Further, the invention should be considered as comprising all possiblecombinations of every feature described in the instant specification,appended claims, and/or drawing figures which may be considered new,inventive and industrially applicable.

Multiple variations and modifications are possible in the embodiments ofthe invention described here. Although certain illustrative embodimentsof the invention have been shown and described here, a wide range ofmodifications, changes and substitutions is contemplated in theforegoing disclosure. While the above description contains manyspecifics, these should not be construed as limitations on the scope ofthe invention, but rather as exemplifications of one or anotherpreferred embodiment thereof. In some instances, some features of thepresent invention may be employed without a corresponding use of theother features.

Accordingly, it is appropriate that the foregoing description beconstrued broadly and understood as being given by way of illustrationand example only, the spirit and scope of the invention being limitedonly by the claims which ultimately issue.

1.-95. (canceled)
 96. A modular package sorting system, comprising: aplurality of sort modules configured to convey a package towards a sortpoint destination of the package; and a plurality of controllers, eachof the plurality of controllers being: associated with one sort modulein the plurality of sort modules, configured to control the associatedone sort module, and configured to communicate with one or more othercontrollers in the plurality of controllers, including to receive andtransmit an electronic packet of data; wherein the electronic packet ofdata comprises the sort point destination of the package.
 97. Themodular package sorting system of claim 96, wherein each of theplurality of controllers is configured to communicate with animmediately subsequent controller of the plurality of controllers and toconvey the package via the associated sort module to the immediatelysubsequent sort module, and to transmit to the immediately subsequentcontroller the sort point destination.
 98. The modular package sortingsystem of claim 96, wherein each of the plurality of controllers iscapable of controlling its respective sort module independently of asorter control computer.
 99. The modular package sorting system of claim96, wherein the plurality of sort modules comprises a series of sortmodules physically connected together end-to-end and being configured toconvey items from a first sort module to a last sort module over theseries of sort modules, wherein each of the plurality of controllers isconfigured to communicate with controllers of the plurality ofcontrollers associated with sort modules just before and just after theassociated sort module in the series, when they exist.
 100. The modularpackage sorting system of claim 99, wherein each controller of theplurality of controllers is programmed to carry out an identicaloperation, the operation comprising receiving the sort point destinationfrom an induction subsystem or from a controller associated with animmediately preceding sort module, using the sort point destination todetermine whether to move the package off the side of the associatedsort module to a sort point or to convey the package to an immediatelysubsequent sort module, and, when conveying the package to theimmediately subsequent sort module, transmitting the sort pointdestination to the controller associated with the immediately subsequentsort module.
 101. The modular package sorting system of claim 96,wherein each of the plurality of sort modules comprises a conveyorsurface configured to move items on the conveyor surface selectively (a)forward towards an immediately subsequent sort module or backwards, (b)to either side, or (c) both (a) and (b); and wherein each controller ofthe plurality of controllers is programmed to reduce speed of theconveyor surface of the associated sort module when an item on theconveyor surface of the associated sort module exceeds a dimensionaland/or weight threshold.
 102. The modular package sorting system ofclaim 101, wherein each controller of the plurality of controllers isprogrammed to reduce speed of the conveyor surface of the associatedsort module when an item on the conveyor surface of the associated sortmodule has a sort point destination located adjacent to an immediatelysubsequent sort module.
 103. The modular package sorting system of claim101, wherein each controller of the plurality of controllers isprogrammed to increase speed of the conveyor surface of the associatedsort module when an item on the conveyor surface of the associated sortmodule has a sort point destination located beyond an immediatelysubsequent sort module and a pre-determined number of subsequent sortmodules have no items on their respective conveyor surfaces.
 104. Themodular package sorting system of claim 96, wherein each of theplurality of controllers is configured to determine, before moving thepackage from the associated sort module to a next sort module, whetheranother package is located on the next sort module and, if so, to waitto move the package onto the next sort module until the another packageis no longer located on the next sort module.
 105. The modular packagesorting system of claim 96, wherein each of the plurality of controllersis further configured to determine a speed among a plurality of speedsat which to send the package to the subsequent sort module, and whereinthe speed determination depends at least on where the package is to bedischarged off the plurality of sort modules.
 106. A modular packagesorting system, comprising: a plurality of sort modules configured toconvey a package to one of a plurality of sortation points, andcomprising a plurality of controllers, each of the plurality ofcontrollers being: associated with one sort module in the plurality ofsort modules, and configured to communicate, when the package is to beconveyed from the associated one sort module to a subsequent sortmodule, with a controller in the plurality of controllers associatedwith the subsequent sort module by transmitting a request for a readymessage to the controller associated with the subsequent sort module andby receiving the ready message from the controller associated with thesubsequent sort module.
 107. The modular package sorting system of claim106, wherein the message received from the controller associated withthe subsequent sort module indicates that the subsequent sort module isready to receive the package.
 108. The modular package sorting system ofclaim 106, wherein each of the plurality of controllers is autonomousfrom a central operator supervisory control.
 109. The modular packagesorting system of claim 106, wherein each of the plurality of sortmodules comprises a conveyor surface configured to move items on theconveyor surface selectively (a) forward towards an immediatelysubsequent sort module or backwards, (b) to either side, or (c) both (a)and (b); and wherein each controller of the plurality of controllers isprogrammed to reduce speed of the conveyor surface of the associatedsort module when an item on the conveyor surface of the associated sortmodule exceeds a dimensional and/or weight threshold.
 110. The modularpackage sorting system of claim 109, wherein each controller of theplurality of controllers is programmed to reduce speed of the conveyorsurface of the corresponding sort module when an item on the conveyorsurface of the corresponding sort module has a sort point destinationlocated adjacent to an immediately subsequent sort module, and/orincrease speed of the conveyor surface of the corresponding sort modulewhen an item on the conveyor surface of the corresponding sort modulehas a sort point destination located beyond an immediately subsequentsort module and a pre-determined number of subsequent sort modules haveno items on their respective conveyor surfaces.
 111. A modular packagesorting system, comprising: a plurality of sort modules configured toconvey a package to a sort point destination of the package andcomprising a plurality of controllers, each of the plurality ofcontrollers being associated with one sort module in the plurality ofsort modules, configured to communicate with one or more othercontrollers in the plurality of controllers, and configured to determinewhether to convey the package from the associated one sort module to asubsequent sort module or off the plurality of sort modules, based onthe sort point destination of the package.
 112. The modular packagesorting system of claim 111, wherein each controller of the plurality ofcontrollers is programmed to reduce speed of a conveyor surface of theassociated sort module when an item on the conveyor surface of theassociated sort module exceeds a dimensional and/or weight threshold.113. The modular package sorting system of claim 111, wherein eachcontroller of the plurality of controllers is programmed to reduce speedof a conveyor surface of the associated sort module when an item on theconveyor surface of the associated sort module has a sort pointdestination located adjacent to an immediately subsequent sort module.114. The modular package sorting system of claim 111, wherein eachcontroller of the plurality of controllers is programmed to increasespeed of a conveyor surface of the associated sort module when an itemon the conveyor surface of the associated sort module has a sort pointdestination located beyond an immediately subsequent sort module and apre-determined number of subsequent sort modules have no items on theirrespective conveyor surfaces.
 115. The modular package sorting system ofclaim 111, further comprising sensors configured to track movement ofthe package across the sort modules, wherein the sensors comprisesensors between the plurality of sort modules to determine when itemspass from one of the plurality of sort modules to another, each suchsensor being associated with the controller associated with the sortmodule before or after the sensor in the plurality of sort modules,wherein the controller associated with the sensor is configured toreport a jam and/or stop the associated sort module when the associatedsensor does not sense an item when expected, based on communicationreceived by the controller associated with the sensor, or when theassociated sensor senses the item for longer than a pre-determinedamount of time.